Thermal energy storage technology is an important topic, as it enables renewable energy technolog... more Thermal energy storage technology is an important topic, as it enables renewable energy technology to be available 24/7 and under different weather conditions. Phase changing materials (PCM) are key players in thermal energy storage, being the most economic among those available with adjustable thermal properties. Paraffin wax (PW) is one of the best materials used in industrial processes to enhance thermal storage. However, the low thermal conductivity of PW prevents its thermal application. In this study, we successfully modified PW based on multi-walled carbon nanotubes (MWCNT) with different concentrations of TiO2—3, 5 and 7 wt.%. The morphology of PCM and its relationship with the chemical structure and stability were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and Thermogravimetric analysis (TGA). As a result, the composites achieved a highest latent heat enthalpy of 176 J/g, in addition to enhanced thermal stability after 15 therm...
Thermal energy storage (TES) technologies are considered as enabling and supporting technologies ... more Thermal energy storage (TES) technologies are considered as enabling and supporting technologies for more sustainable and reliable energy generation methods such as solar thermal and concentrated solar power. A thorough investigation of the TES system using paraffin wax (PW) as a phase changing material (PCM) should be considered. One of the possible approaches for improving the overall performance of the TES system is to enhance the thermal properties of the energy storage materials of PW. The current study investigated some of the properties of PW doped with nano-additives, namely, multi-walled carbon nanotubes (MWCNs), forming a nanocomposite PCM. The paraffin/MWCNT composite PCMs were tailor-made for enhanced and efficient TES applications. The thermal storage efficiency of the current TES bed system was approximately 71%, which is significant. Scanning electron spectroscopy (SEM) with energy dispersive X-ray (EDX) characterization showed the physical incorporation of MWCNTs wit...
Nanocomposites of silica gel (SG) and multiwalled carbon nanotubes (MWCNTs) of relatively low con... more Nanocomposites of silica gel (SG) and multiwalled carbon nanotubes (MWCNTs) of relatively low concentrations (0.25, 0.50, and 0.75 wt%) were characterized before and after annealing. Adsorption is a surface phenomenon, and based on this, the morphology of the composites was investigated by scanning electron microscopy (SEM). The produced images show that the MWCNTs were embedded into the silica gel base material. Fourier transform infrared (FTIR) transmittance spectroscopy showed that MWCNTs were not functionalized within the matrix of silica gel and MWCNT composites. However, after annealing the composites at 400 °C for 4 h in air, evidence of activation was observed in the FTIR spectrum. The effects of the embedding of MWCNTs on porosity, specific surface area, and pore size distribution were studied using Raman spectroscopy. The Raman spectra of the prepared composites were mainly dominated by characteristic sharp scattering peaks of the silica gel at 480, 780, and 990 cm−1 and a...
One of the main challenges of the production of a blue laser is the preparation of defect-free Ga... more One of the main challenges of the production of a blue laser is the preparation of defect-free GaN layers. It is of high tehnological interest to characterize GaN nanomembrane mechanically for further advanced applications. The current study addresses the impact of applied stresses on GaN nanomembranes, which are placed on sapphire the substrates, using nanoindentation as a nondestructive test. The mechanical response of the 20, and 100 nm thin GaN nanomembrane were studied at different normal applied loads ranging from 1 mN down to 0.1 mN using the Berkovich nanoindentation technique. There were plastic deformation regions at the nanoindented GaN nanomembranes monitored by the load-displacement (p-h) curves. The depth of the deformed regions increased with increasing the applied loads on the diamond indenter. Beside the in-situ depth estimation of the residual nanoindentation using the instrumented nanoindentation machine, Atomic Force Microscopy (AFM) has been deployed as an ex-si...
... Biographical notes: Maha MO Khayyat is an Assistant Professor of Physics in the Faculty ... A... more ... Biographical notes: Maha MO Khayyat is an Assistant Professor of Physics in the Faculty ... AliMansoori, G. (2005) Principles of Nanotechnology Molecular-Based Study of Condensed Matter in ... CS, Thelakkat, M. and Willert-Porada, M. (2006) Proceedings of Symposium F on Thin ...
Crystalline semiconducting micro/nanowires have been grown using various precursors and fabricate... more Crystalline semiconducting micro/nanowires have been grown using various precursors and fabricated by defining the nanowires in or from a crystalline material. A micro/nanowire is either a free standing crystal or a crystal that has been modified to define a one dimensional unit in which the features along two of the dimensions are on the micro/nanometer scale and the features on the other dimension are much larger. Nanowires have been proposed or used for applications including lasers, transistors, and solar cells. It has been speculated that they could present great technical and material advantages in these optoelectronic devices.[1-2] Nanowires are advantageous for use in large scale photovoltaic applications primarily because lower cost materials can be used, since the geometry of a core/shell nanowire solar cell (the core of the nanowire having a different doping than the shell or shells) may give adequate solar cell efficiencies with lower quality materials.[3] Free-standing core shell structures are desirable: these types of structure have good efficiency at possibly lower cost because the adsorption of light is good, compared to thin planar layers, and the diffusion length needed to collect carriers is much smaller as compared with thicker planar layers (see FIG. 1). In all cases, for nanowire photovoltaic devices the area of the p-n junction is larger than for similar planar devices. This means that the dark current in these devices is fundamentally higher than for planar devices with similar dimensions. The higher dark current has a negative effect on the solar cell efficiency, but it is believed that the advantages of carrier collection efficiency and/or light adsorption can outweigh this effect to make it possible to produce cost-effective nanowire based solar cells.[3]
Raman spectroscopy, which is a non-destructive technique, has been used to investigate the effect... more Raman spectroscopy, which is a non-destructive technique, has been used to investigate the effect of sample temperature on indentation-induced crystallographic phase transitions in crystalline silicon and amorphous silicon films deposited on a sapphire crystal. It has been shown that in both types of sample, whereas 300 K Vickers diamond indentations lead to the transformation to the Si-II phase during indenter loading on the crystalline and amorphous samples, there is no such transformation in either sample when it is cooled down to 77 K. An explanation of the experimental results has been provided using the pressure-temperature phase diagram of silicon.
It has been known for about 15 years that when a Vickers indenter is loaded on to a crystalline s... more It has been known for about 15 years that when a Vickers indenter is loaded on to a crystalline semiconductor, such as silicon, a semiconductor to metallic phase transition occurs during indenter loading and on removal of the indenter the material within the residual indentation becomes amorphous. Here we report a completely opposite effect: when a Berkovich or Vickers diamond indenter is loaded onto a submicrometer thick film of amorphous germanium, it crystallizes and undergoes structural phase transitions. These observations are based on our transmission electron microscopy and Raman scattering investigations, which have been described. It has also been shown that the indentation-induced crystallization and phase transitions occur close to the indenter tip, where the plastic strains are the highest.
Using four-terminal in-situ dc electrical resistance measurements and Raman spectra of residual V... more Using four-terminal in-situ dc electrical resistance measurements and Raman spectra of residual Vickers indentations in single crystals of Si ͑100͒, it has been shown that the sample temperature, in the range of 150 to 300 K, at which a Vickers diamond indentation is made, has a strong influence on the occurrence of indentation-induced phase transitions within the plastically deformed zone around the indentation. A consistent explanation of the experimental results, based on an existing theoretical pressure-temperature phase diagram of silicon, has been provided.
Firstly, the authors state, However, no direct evidence has been given in previous indentation s... more Firstly, the authors state, However, no direct evidence has been given in previous indentation studies of to confirm that a phase transformation had actually occurred. In fact, in a recent publication, Raman spectroscopy was used to show clearly that when a Vickers diamond ...
It has been known for about 15 years that when a Vickers indenter is loaded on to a crystalline s... more It has been known for about 15 years that when a Vickers indenter is loaded on to a crystalline semiconductor, such as silicon, a semiconductor to metallic phase transition occurs during indenter loading and on removal of the indenter the material within the residual indentation becomes amorphous. Here we report a completely opposite effect: when a Berkovich or Vickers diamond indenter is loaded onto a submicrometer thick film of amorphous germanium, it crystallizes and undergoes structural phase transitions. These observations are based on our transmission electron microscopy and Raman scattering investigations, which have been described. It has also been shown that the indentation-induced crystallization and phase transitions occur close to the indenter tip, where the plastic strains are the highest.
International Journal of Nano and Biomaterials, 2009
It has been known for about 15 years that when a Vickers indenter is loaded on to a crystalline s... more It has been known for about 15 years that when a Vickers indenter is loaded on to a crystalline semiconductor, such as silicon, a semiconductor to metallic phase transition occurs during indenter loading and on removal of the indenter the material within the residual indentation becomes amorphous. Here we report a completely opposite effect: when a Berkovich or Vickers diamond indenter is loaded onto a submicrometer thick film of amorphous germanium, it crystallizes and undergoes structural phase transitions. These observations are based on our transmission electron microscopy and Raman scattering investigations, which have been described. It has also been shown that the indentation-induced crystallization and phase transitions occur close to the indenter tip, where the plastic strains are the highest.
Raman microscopy has been used to investigate phase transitions within Vickers diamond residual i... more Raman microscopy has been used to investigate phase transitions within Vickers diamond residual indentations, made at room temperature and at 77 K, in single crystal Si(100) and 0.3 mum thick amorphous silicon film deposited on a sapphire single crystal. It has been found that for room temperature residual indentations in the single crystal silicon (Si-I) and amorphous silicon film phase transition to the Si-III phase occurs, as indicated by the existence of Raman peaks corresponding to this phase. On the other hand, in the case of the indentations made at 77 K, only the Si-I crystalline phase and amorphous silicon were found within the residual indentations. It has been suggested that when Vickers diamond indentations are made at 77 K, there is no phase transition to the Si-II (i.e. the beta-Sn phase) during indenter loading, which would give rise to the Si-III phase on the removal of indenter load. Moreover, the existence of a very strong peak due to the Si-I phase gives further support to the suggestion that during Vickers indentations in single crystal silicon and in amorphous silicon at 77 K there is no structural phase transition. It has also been suggested that during room temperature indentations there is a substantial temperature rise, which may help to cause structural phase transitions.
Using four-terminal in-situ dc electrical resistance measurements and Raman spectra of residual V... more Using four-terminal in-situ dc electrical resistance measurements and Raman spectra of residual Vickers indentations in single crystals of Si (100), it has been shown that the sample temperature, in the range of 150 to 300 K, at which a Vickers diamond indentation is made, has a strong influence on the occurrence of indentation-induced phase transitions within the plastically deformed zone around the indentation. A consistent explanation of the experimental results, based on an existing theoretical pressure-temperature phase diagram of silicon, has been provided.
Raman microscopy has been used to investigate phase transitions within Vickers diamond residual i... more Raman microscopy has been used to investigate phase transitions within Vickers diamond residual indentations, made at room temperature and at 77 K, in single crystal Si(100) and 0.3 µm thick amorphous silicon film deposited on a sapphire single crystal. It has been found that for room temperature residual indentations in the single crystal silicon (Si-I) and amorphous silicon film phase transition to the Si-III phase occurs, as indicated by the existence of Raman peaks corresponding to this phase. On the other hand, in the case of the indentations made at 77 K, only the Si-I crystalline phase and amorphous silicon were found within the residual indentations. It has been suggested that when Vickers diamond indentations are made at 77 K, there is no phase transition to the Si-II (i.e. the β-Sn phase) during indenter loading, which would give rise to the Si-III phase on the removal of indenter load. Moreover, the existence of a very strong peak due to the Si-I phase gives further support to the suggestion that during Vickers indentations in single crystal silicon and in amorphous silicon at 77 K there is no structural phase transition. It has also been suggested that during room temperature indentations there is a substantial temperature rise, which may help to cause structural phase transitions.
Firstly, the authors state, However, no direct evidence has been given in previous indentation s... more Firstly, the authors state, However, no direct evidence has been given in previous indentation studies of to confirm that a phase transformation had actually occurred. In fact, in a recent publication, Raman spectroscopy was used to show clearly that when a Vickers diamond ...
ABSTRACT Raman spectroscopy, which is a non-destructive technique, has been used to investigate t... more ABSTRACT Raman spectroscopy, which is a non-destructive technique, has been used to investigate the effect of sample temperature on indentation-induced crystallographic phase transitions in crystalline silicon and amorphous silicon films deposited on a sapphire crystal. It has been shown that in both types of sample, whereas 300 K Vickers diamond indentations lead to the transformation to the Si-II phase during indenter loading on the crystalline and amorphous samples, there is no such transformation in either sample when it is cooled down to 77 K. An explanation of the experimental results has been provided using the pressure–temperature phase diagram of silicon.
Thermal energy storage technology is an important topic, as it enables renewable energy technolog... more Thermal energy storage technology is an important topic, as it enables renewable energy technology to be available 24/7 and under different weather conditions. Phase changing materials (PCM) are key players in thermal energy storage, being the most economic among those available with adjustable thermal properties. Paraffin wax (PW) is one of the best materials used in industrial processes to enhance thermal storage. However, the low thermal conductivity of PW prevents its thermal application. In this study, we successfully modified PW based on multi-walled carbon nanotubes (MWCNT) with different concentrations of TiO2—3, 5 and 7 wt.%. The morphology of PCM and its relationship with the chemical structure and stability were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and Thermogravimetric analysis (TGA). As a result, the composites achieved a highest latent heat enthalpy of 176 J/g, in addition to enhanced thermal stability after 15 therm...
Thermal energy storage (TES) technologies are considered as enabling and supporting technologies ... more Thermal energy storage (TES) technologies are considered as enabling and supporting technologies for more sustainable and reliable energy generation methods such as solar thermal and concentrated solar power. A thorough investigation of the TES system using paraffin wax (PW) as a phase changing material (PCM) should be considered. One of the possible approaches for improving the overall performance of the TES system is to enhance the thermal properties of the energy storage materials of PW. The current study investigated some of the properties of PW doped with nano-additives, namely, multi-walled carbon nanotubes (MWCNs), forming a nanocomposite PCM. The paraffin/MWCNT composite PCMs were tailor-made for enhanced and efficient TES applications. The thermal storage efficiency of the current TES bed system was approximately 71%, which is significant. Scanning electron spectroscopy (SEM) with energy dispersive X-ray (EDX) characterization showed the physical incorporation of MWCNTs wit...
Nanocomposites of silica gel (SG) and multiwalled carbon nanotubes (MWCNTs) of relatively low con... more Nanocomposites of silica gel (SG) and multiwalled carbon nanotubes (MWCNTs) of relatively low concentrations (0.25, 0.50, and 0.75 wt%) were characterized before and after annealing. Adsorption is a surface phenomenon, and based on this, the morphology of the composites was investigated by scanning electron microscopy (SEM). The produced images show that the MWCNTs were embedded into the silica gel base material. Fourier transform infrared (FTIR) transmittance spectroscopy showed that MWCNTs were not functionalized within the matrix of silica gel and MWCNT composites. However, after annealing the composites at 400 °C for 4 h in air, evidence of activation was observed in the FTIR spectrum. The effects of the embedding of MWCNTs on porosity, specific surface area, and pore size distribution were studied using Raman spectroscopy. The Raman spectra of the prepared composites were mainly dominated by characteristic sharp scattering peaks of the silica gel at 480, 780, and 990 cm−1 and a...
One of the main challenges of the production of a blue laser is the preparation of defect-free Ga... more One of the main challenges of the production of a blue laser is the preparation of defect-free GaN layers. It is of high tehnological interest to characterize GaN nanomembrane mechanically for further advanced applications. The current study addresses the impact of applied stresses on GaN nanomembranes, which are placed on sapphire the substrates, using nanoindentation as a nondestructive test. The mechanical response of the 20, and 100 nm thin GaN nanomembrane were studied at different normal applied loads ranging from 1 mN down to 0.1 mN using the Berkovich nanoindentation technique. There were plastic deformation regions at the nanoindented GaN nanomembranes monitored by the load-displacement (p-h) curves. The depth of the deformed regions increased with increasing the applied loads on the diamond indenter. Beside the in-situ depth estimation of the residual nanoindentation using the instrumented nanoindentation machine, Atomic Force Microscopy (AFM) has been deployed as an ex-si...
... Biographical notes: Maha MO Khayyat is an Assistant Professor of Physics in the Faculty ... A... more ... Biographical notes: Maha MO Khayyat is an Assistant Professor of Physics in the Faculty ... AliMansoori, G. (2005) Principles of Nanotechnology Molecular-Based Study of Condensed Matter in ... CS, Thelakkat, M. and Willert-Porada, M. (2006) Proceedings of Symposium F on Thin ...
Crystalline semiconducting micro/nanowires have been grown using various precursors and fabricate... more Crystalline semiconducting micro/nanowires have been grown using various precursors and fabricated by defining the nanowires in or from a crystalline material. A micro/nanowire is either a free standing crystal or a crystal that has been modified to define a one dimensional unit in which the features along two of the dimensions are on the micro/nanometer scale and the features on the other dimension are much larger. Nanowires have been proposed or used for applications including lasers, transistors, and solar cells. It has been speculated that they could present great technical and material advantages in these optoelectronic devices.[1-2] Nanowires are advantageous for use in large scale photovoltaic applications primarily because lower cost materials can be used, since the geometry of a core/shell nanowire solar cell (the core of the nanowire having a different doping than the shell or shells) may give adequate solar cell efficiencies with lower quality materials.[3] Free-standing core shell structures are desirable: these types of structure have good efficiency at possibly lower cost because the adsorption of light is good, compared to thin planar layers, and the diffusion length needed to collect carriers is much smaller as compared with thicker planar layers (see FIG. 1). In all cases, for nanowire photovoltaic devices the area of the p-n junction is larger than for similar planar devices. This means that the dark current in these devices is fundamentally higher than for planar devices with similar dimensions. The higher dark current has a negative effect on the solar cell efficiency, but it is believed that the advantages of carrier collection efficiency and/or light adsorption can outweigh this effect to make it possible to produce cost-effective nanowire based solar cells.[3]
Raman spectroscopy, which is a non-destructive technique, has been used to investigate the effect... more Raman spectroscopy, which is a non-destructive technique, has been used to investigate the effect of sample temperature on indentation-induced crystallographic phase transitions in crystalline silicon and amorphous silicon films deposited on a sapphire crystal. It has been shown that in both types of sample, whereas 300 K Vickers diamond indentations lead to the transformation to the Si-II phase during indenter loading on the crystalline and amorphous samples, there is no such transformation in either sample when it is cooled down to 77 K. An explanation of the experimental results has been provided using the pressure-temperature phase diagram of silicon.
It has been known for about 15 years that when a Vickers indenter is loaded on to a crystalline s... more It has been known for about 15 years that when a Vickers indenter is loaded on to a crystalline semiconductor, such as silicon, a semiconductor to metallic phase transition occurs during indenter loading and on removal of the indenter the material within the residual indentation becomes amorphous. Here we report a completely opposite effect: when a Berkovich or Vickers diamond indenter is loaded onto a submicrometer thick film of amorphous germanium, it crystallizes and undergoes structural phase transitions. These observations are based on our transmission electron microscopy and Raman scattering investigations, which have been described. It has also been shown that the indentation-induced crystallization and phase transitions occur close to the indenter tip, where the plastic strains are the highest.
Using four-terminal in-situ dc electrical resistance measurements and Raman spectra of residual V... more Using four-terminal in-situ dc electrical resistance measurements and Raman spectra of residual Vickers indentations in single crystals of Si ͑100͒, it has been shown that the sample temperature, in the range of 150 to 300 K, at which a Vickers diamond indentation is made, has a strong influence on the occurrence of indentation-induced phase transitions within the plastically deformed zone around the indentation. A consistent explanation of the experimental results, based on an existing theoretical pressure-temperature phase diagram of silicon, has been provided.
Firstly, the authors state, However, no direct evidence has been given in previous indentation s... more Firstly, the authors state, However, no direct evidence has been given in previous indentation studies of to confirm that a phase transformation had actually occurred. In fact, in a recent publication, Raman spectroscopy was used to show clearly that when a Vickers diamond ...
It has been known for about 15 years that when a Vickers indenter is loaded on to a crystalline s... more It has been known for about 15 years that when a Vickers indenter is loaded on to a crystalline semiconductor, such as silicon, a semiconductor to metallic phase transition occurs during indenter loading and on removal of the indenter the material within the residual indentation becomes amorphous. Here we report a completely opposite effect: when a Berkovich or Vickers diamond indenter is loaded onto a submicrometer thick film of amorphous germanium, it crystallizes and undergoes structural phase transitions. These observations are based on our transmission electron microscopy and Raman scattering investigations, which have been described. It has also been shown that the indentation-induced crystallization and phase transitions occur close to the indenter tip, where the plastic strains are the highest.
International Journal of Nano and Biomaterials, 2009
It has been known for about 15 years that when a Vickers indenter is loaded on to a crystalline s... more It has been known for about 15 years that when a Vickers indenter is loaded on to a crystalline semiconductor, such as silicon, a semiconductor to metallic phase transition occurs during indenter loading and on removal of the indenter the material within the residual indentation becomes amorphous. Here we report a completely opposite effect: when a Berkovich or Vickers diamond indenter is loaded onto a submicrometer thick film of amorphous germanium, it crystallizes and undergoes structural phase transitions. These observations are based on our transmission electron microscopy and Raman scattering investigations, which have been described. It has also been shown that the indentation-induced crystallization and phase transitions occur close to the indenter tip, where the plastic strains are the highest.
Raman microscopy has been used to investigate phase transitions within Vickers diamond residual i... more Raman microscopy has been used to investigate phase transitions within Vickers diamond residual indentations, made at room temperature and at 77 K, in single crystal Si(100) and 0.3 mum thick amorphous silicon film deposited on a sapphire single crystal. It has been found that for room temperature residual indentations in the single crystal silicon (Si-I) and amorphous silicon film phase transition to the Si-III phase occurs, as indicated by the existence of Raman peaks corresponding to this phase. On the other hand, in the case of the indentations made at 77 K, only the Si-I crystalline phase and amorphous silicon were found within the residual indentations. It has been suggested that when Vickers diamond indentations are made at 77 K, there is no phase transition to the Si-II (i.e. the beta-Sn phase) during indenter loading, which would give rise to the Si-III phase on the removal of indenter load. Moreover, the existence of a very strong peak due to the Si-I phase gives further support to the suggestion that during Vickers indentations in single crystal silicon and in amorphous silicon at 77 K there is no structural phase transition. It has also been suggested that during room temperature indentations there is a substantial temperature rise, which may help to cause structural phase transitions.
Using four-terminal in-situ dc electrical resistance measurements and Raman spectra of residual V... more Using four-terminal in-situ dc electrical resistance measurements and Raman spectra of residual Vickers indentations in single crystals of Si (100), it has been shown that the sample temperature, in the range of 150 to 300 K, at which a Vickers diamond indentation is made, has a strong influence on the occurrence of indentation-induced phase transitions within the plastically deformed zone around the indentation. A consistent explanation of the experimental results, based on an existing theoretical pressure-temperature phase diagram of silicon, has been provided.
Raman microscopy has been used to investigate phase transitions within Vickers diamond residual i... more Raman microscopy has been used to investigate phase transitions within Vickers diamond residual indentations, made at room temperature and at 77 K, in single crystal Si(100) and 0.3 µm thick amorphous silicon film deposited on a sapphire single crystal. It has been found that for room temperature residual indentations in the single crystal silicon (Si-I) and amorphous silicon film phase transition to the Si-III phase occurs, as indicated by the existence of Raman peaks corresponding to this phase. On the other hand, in the case of the indentations made at 77 K, only the Si-I crystalline phase and amorphous silicon were found within the residual indentations. It has been suggested that when Vickers diamond indentations are made at 77 K, there is no phase transition to the Si-II (i.e. the β-Sn phase) during indenter loading, which would give rise to the Si-III phase on the removal of indenter load. Moreover, the existence of a very strong peak due to the Si-I phase gives further support to the suggestion that during Vickers indentations in single crystal silicon and in amorphous silicon at 77 K there is no structural phase transition. It has also been suggested that during room temperature indentations there is a substantial temperature rise, which may help to cause structural phase transitions.
Firstly, the authors state, However, no direct evidence has been given in previous indentation s... more Firstly, the authors state, However, no direct evidence has been given in previous indentation studies of to confirm that a phase transformation had actually occurred. In fact, in a recent publication, Raman spectroscopy was used to show clearly that when a Vickers diamond ...
ABSTRACT Raman spectroscopy, which is a non-destructive technique, has been used to investigate t... more ABSTRACT Raman spectroscopy, which is a non-destructive technique, has been used to investigate the effect of sample temperature on indentation-induced crystallographic phase transitions in crystalline silicon and amorphous silicon films deposited on a sapphire crystal. It has been shown that in both types of sample, whereas 300 K Vickers diamond indentations lead to the transformation to the Si-II phase during indenter loading on the crystalline and amorphous samples, there is no such transformation in either sample when it is cooled down to 77 K. An explanation of the experimental results has been provided using the pressure–temperature phase diagram of silicon.
Uploads
Papers by Maha Khayyat