Point perturbations

This chapter discusses the energetics of point perturbations arising from intrinsic and extrinsic defects, and intentional and unintentional impurities. Point perturbations can be short range or long range. This requires the inclusion of core potential, exchange correlation and Hartree or Hartree-Fock potential. Hubbard energy, which is useful for Hartree calculations in a localized state, is introduced. An approach to calculating the behavior arising in shallow dopants (long range) and deep centers (short range) is presented. The tight binding defect-molecule model is used to explore the appearance of bonding and antibonding states in vacancies, interstitials and substitutional deep centers and some common complexes, such as the DX center, using configuration coordinates to understand the electronic and lattice energy contributions in the defect behavior. Finally, the chapter summarizes other important centers, such as the Pb center and the F center, before reviewing the implications of centers in light interaction and Poole-Frenkel conduction.

Photosensitivity of MESFETs on Epitaxy Layers of GaAs with Monocrystalline Silicon Wafer

In this paper described researched essentials and physical mechanisms which determine photosensitivity of MESFET on epitaxy layers of GaAs with monocrystalline silicon wafer under their illumination in impure zone absorption spectrum. Conducted experiments showed that source current changing with the type of deep centers, change of value is determined by two factors: change width of volumetric charge barrier contact layer and width of dipole layer on border section of active heterojunction layer of Si-wafer.

Влияние глубоких центров на статистическую задержку микроплазменного пробоя в арсенид-галлиевых светодиодах

A statistical study of the microplasma-breakdown delay in gallium-arsenide light-emitting diodes is performed. The significant effect of deep centers on the microplasma breakdown of gallium arsenide p–n junctions is detected. It is shown that the statistical delay of the microplasma breakdown makes it possible to estimate the energy spectrum of deep levels in the microplasma channel when varying the charge state of deep centers by decreasing the reverse voltage applied to the p–n junction. In the temperature range of 250–350 K, the effect of three deep levels is detected and their parameters are determined.