Papers by Hariton Polatoglou
EPL, Mar 1, 1992
Theoretical calculations for the energy band structure as well as for the optical transitions at ... more Theoretical calculations for the energy band structure as well as for the optical transitions at the centre Γ of the superlattice Brillouin zone are presented for (Si)3/(Ge)4 superlattices grown on SixGe1-x(001) substrates. These superlattices belong to the D4h19 symmetry (n + m = odd). The influence of the alloy buffer (on which the superlattice is considered to be grown) on the transition energies and probabilities and the nature of the gap (direct/indirect) is investigated. It is found that for some Si concentrations x in the buffer alloy the superlattices become direct-gap semiconductors with significant transition probabilities. Moreover, the dependence of the preceding features on the valence band offset is also examined and it is found that the latter does not influence them drastically.
NATO ASI Series, 1989
A similarity transformation of the superlattice Hamiltonian is presented. The transformed Hamilto... more A similarity transformation of the superlattice Hamiltonian is presented. The transformed Hamiltonian includes two parts. One that describes the average crystal, and the other the interaction between average crystal states. This interaction is small and is treated as a perturbation. The method is applied to GaSb/InAs (100) superlattice, and its band structure is analyzed.
Thin Solid Films, 1992
We study a five-period Si 4 /Ge 4 superlattice embedded in a 40 layer silicon spacer ((Si 4 /Ge 4... more We study a five-period Si 4 /Ge 4 superlattice embedded in a 40 layer silicon spacer ((Si 4 /Ge 4 ) 5 (Si) 40 ) and a five-period Si 4 /Ge 6 superlattice embedded in a 48-layer germanium spaced ((Si 4 /Ge 6 ) 5 (Ge) 48 ). Results concerning the band structure, spatial behaviour of the ...
Semiconductor Science and Technology, 1993
The energy band structure (nature of the bandgap, optical transitions) for the strained (Si)12/(G... more The energy band structure (nature of the bandgap, optical transitions) for the strained (Si)12/(Ge)4 and (Si)16/(Ge)4 superlattices grown on a Si(001) substrate is presented. The calculations predict that these materials are almost direct--gap semiconductors, but with very small transition probabilities across the direct gap. These findings are discussed in connection with experimental data.
Superlattices and Microstructures, Oct 1, 2006
The structural and optical properties of GaP and GaPN layers synthesized by molecular-beam epitax... more The structural and optical properties of GaP and GaPN layers synthesized by molecular-beam epitaxy on Si(100) substrates misoriented by 4° are studied. The possibility of producing GaP buffer layers that exhibit a high degree of heterointerface planarity and an outcropping dislocation density of no higher thañ 2 × 10 8 cm-2 is shown. Emission from the Si/GaP/GaPN structure in the spectral range of 630-640 nm at room temperature is observed. Annealing during growth of the Si/GaP/GaPN structure makes it possible to enhance the room-temperature photoluminescence intensity by a factor of 2.6, with no shift of the maximum of the emission line.
ICERI2021 Proceedings, 2021
Proceedings of the 8th International Conference on Software Development and Technologies for Enhancing Accessibility and Fighting Info-exclusion, 2018
The aim of the present work is to propose a course on fields of Science, Technology,Engineeringan... more The aim of the present work is to propose a course on fields of Science, Technology,Engineeringand Mathematics (STEM) subjects which is very suitable for the inclusion of persons with disabilities in the classroom. We developed an interdisciplinary STEM project based on the Arduino platform. It has bearing on the constructivist theory and it considers the principle of the learning communities and the differentiated instruction. Its target group is an inhomogeneous groupof students from middle and high school and some students with hearing disabilities. The deaf students are using the Greek Sign Language (GSL). From literature, it becomes evident the low participation of students with disabilities in subjects related to STEM education. The designed course is based on the Arduino platform and aims at solving an authentic problem. We describe the difficulties that we confronted, especially concerning attitudes about STEM subjects and the necessary adaptations. One of the authors worked as an interpreter for the GSL. The students with hearing disabilities participated in equal terms with other students and achieved comparable results. This is a proof that they acquired the required skills and attitudes for such a complex process. In addition, it deemed necessary to enhance the GSL with new signs to facilitate the communication.
NATO ASI Series, 1996
Internal boundaries influence the properties of materials and have therefore attracted due attent... more Internal boundaries influence the properties of materials and have therefore attracted due attention1–4. Of particular importance are the internal boundaries in load-bearing intermetallics as they effect their mechanical properties5. Many interesting phenomena can occur at the boundaries, like segregation6, wetting7,8, and for the softly-ordered intermetallics, wetting by the disordered phase9–11. A problem that hidders the study of the boundaries is that they are not easily accessible to the experimental probes, or different probes are needed to access their different aspects, like the structure of the boundary, the presence of segregated atoms and their chemical indentity, and their relation to the material properties2,12. On the other hand theoretical methods have been progressed to a point where predictions of material properties of bulk crystals and planar defects like boundaries and surfaces are possible1–3. It is certain that, using more powerful computers and order-N methods, it will be routine to study new materials. At present, the study of the thermodynamics of alloys and intermetallics and their defects necessitates, simpler methods. A simple method which was successful to address the effects of segregation at boundaries is the Monte-Carlo method utilizing a N-body semiempirical potential6.
The process of reproduction in nature is approached by the means of an abstract population and a ... more The process of reproduction in nature is approached by the means of an abstract population and a simple stochastic algorithm. The algorithm’s results appear to be predictable. When the Mendelian rules of inheritance are being used, natural selection has no effect on the population, all its members are equally qualified for reproduction, and the Hardy-Weinberg principle is found.
Journal of Chemical Education, 2006
ABSTRACT If we look into the past we will discover that the teachers of thermodynamics were alway... more ABSTRACT If we look into the past we will discover that the teachers of thermodynamics were always trying to interpret an important part of their science by using geometry. The relation between geometry and thermodynamics is of great interest and importance in teaching thermodynamics. This article examines the way undergraduate students of thermodynamics study the ideal gas case and handle its fundamental functions by using geometric objects like surfaces and common computer software. The results indicate that students find the graphical method of elaborating a fundamental function of a system efficient and easy to use. Since basic mathematics and computer skills are required, we conclude that the method is an efficient way of making not only qualitative interpretations, but also quantitative assessments of the behavior of any thermodynamic system. Keywords (Audience): Second-Year Undergraduate
Journal of Physics: Conference Series, 2005
... Page 2. Stress distribution, strains and energetics of Si-capped Ge quantum dots: An atomisti... more ... Page 2. Stress distribution, strains and energetics of Si-capped Ge quantum dots: An atomistic simulation study N Skoulidis and HM Polatoglou Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki Email: [email protected]; [email protected] Abstract. ...
International Journal of Online Engineering (iJOE), Jan 25, 2018
In this paper we propose a scenario for secondary education at which students could estimate the ... more In this paper we propose a scenario for secondary education at which students could estimate the temperature, the radius and the age of stars. To achieve this, we built a virtual real experiment which can be performed from distance on any portable device. Students can connect to a webpage and choose a star from a list. After applying B and V filters they obtain the B and V magnitude. Consequently, they calculate the B-V index of a star and using a simple formula they estimate the star's surface temperature. Furthermore, guided through a worksheet and with the use of Hertzsprung-Russell diagram they can estimate the radius and the age of the star.
World Journal of Education, 2019
Education for Sustainable Development (ESD) is an important issue for the education of students w... more Education for Sustainable Development (ESD) is an important issue for the education of students worldwide becauseit offers knowledge, skills, attitudes and values necessary to ensure a sustainable future for humanity at local andglobal levels, which is nowadays becoming critical. The decade 2005-2014 called ‘Decade of ESD’ was an initiativeby the United Nations to promote ESD worldwide, followed currently by the Agenda 2030. ESD should be anongoing subject for students in formal and informal education, at all educational levels, and in life-long learningprograms, starting with early childhood education. This paper reports on the knowledge, perceptions and attitudes ofpre-service early childhood teachers of the University of Ioannina, Greece, on ESD using a quantitative approachutilizing a questionnaire. Our findings showed that most pre-service teachers had knowledge on environmentalaspects but did not consider societal and financial matters to be aspects of ESD. Furthermore, most s...
International Journal of Online Engineering (iJOE), 2018
In this work, we present research results concerning students’ acceptance of the implementation o... more In this work, we present research results concerning students’ acceptance of the implementation of remote experiments in secondary education. We discuss-analyze two discrete ways of conducting remote experiments and we compare the pertinent data on acceptance. Disparities emerge when the same remote experiments are used as demonstration experiments in classroom and by the students from their own place (assigned homework). The latter seems to be more the favorable for the students to participate in remote experimentation.
Journal of Physics C: Solid State Physics, 1983
... Printed in Great Britain Bonding in cubic and rhombohedral GeTe HM Polatoglou, G Theodorou an... more ... Printed in Great Britain Bonding in cubic and rhombohedral GeTe HM Polatoglou, G Theodorou and NA Economou Physics Department, Aristoteles University of Thessaloniki, Greece Received 7 May 1982 ... CSD Page 3. 818 H M Polatoglou, G Theodorou and N A Economou ...
Lecture Notes in Physics
The pseudopotential method is used to obtain the band structure and electronic d4nsity of states ... more The pseudopotential method is used to obtain the band structure and electronic d4nsity of states for both cubic and rhombohedral GeTe. We find that the minimum energy gap occurs along the line LK. Our calculations also show that the rhombohedral distortion lowers the electronic energy. In addition the reflectance spectra are obtained for the cubic GeTe and compared with experimental data.
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Papers by Hariton Polatoglou
Το περιβάλλον είναι πολύ βασικό για την επιβίωση του ανθρώπου. Σε παλαιότερες εποχές, η μικρή τεχνολογική ανάπτυξη ανάγκαζε τους ανθρώπους να διαχειρίζονται καλύτερα τους περιβαλλοντικούς πόρους . Σήμερα η τεχνολογική ανάπτυξη έχει λύσει αρκετά προβλήματα ως προς την παραγωγή και αποθήκευση/μεταφορά των πόρων, αγνοώντας πολλές φορές το πρόβλημα της βιώσιμης ανάπτυξης (sustainable development).