Fermi Energy

Electronic transport in ferromagnetic ballistic conductors is predicted to exhibit ballistic anisotropic magnetoresistance—a change in the ballistic conductance with the direction of magnetization. This phenomenon originates from the effect of the spin-orbit interaction on the electronic band structure which leads to a change in the number of bands crossing the Fermi energy when the magnetization direction changes. We illustrate the

The midgap density of states (MGDOS) and junction properties of a-Si : H and a-SiGe : H alloys are investigated by admittance measurements on p-i-n solar cells. An expression for the capacitance is derived from the frequency, temperature, and bias dependence of the deep state response. The measured admittance is analyzed with an equivalent circuit model. The density of states go, attempt-to-escape frequency v, and the Fermi energy EF are adjusted to fit the measured admittance. Close agreement is found with the measured capacitance and conductance over a wide range of temperature and frequency. The single junction model is shown to apply equally well to pi-n and Schottky diodes, justifying the neglect of the n-i junction and thin doped layers in the p-i-n device analysis. Fitted values of go are confirmed by values of go obtained from the limiting capacitance at high temperature. The MGDOS increases exponentially from (1-2) x in16 to (3-4) x i0"/cm3 . eV as the Ge increases from 0 to 62%, in good general agreement with results of others. This study extends previous admittance work on thick a-Si : H Schottky barriers to thin ( < 1 pm) a-Si : H and a-SiGe : H p-i-n junctions.