The DR in Accumulation and Inversion Layers of Non-parabolic Semiconductors Under Magnetic Quantization

Abstract

This chapter explores the DR in inversion and accumulation layers of nonlinear optical semiconductors based on a newly formulated electron dispersion relation considering all types of anisotropies of the energy band spectrum within the framework of k.p formalism. We have also investigated the DRs in inversion and accumulation layers of III–V, II–VI, IV–VI, stressed Kane type semiconductors and Ge, respectively. The DOS functions for all the materials in this case are series of non-uniformly distributed Dirac’s Delta functions at specified quantized points in the respective energy axis. The spacing between the consecutive Delta functions are functions of energy band constants and quantization of the wave vector space of a particular material. The DOS function needs two summations namely one summation over the Landau quantum number and the other one is due to formation of such layers.It may be noted that the energy levels in inversion and accumulation layers of various materials lead to the discrete energy levels, somewhat like atomic energy levels, which produce very large changes. This follows from the inherent nature of the quantum confinement of the carrier gas dealt with here. In the present case, there remain no free carrier states in between any two allowed sets of totally quantized levels in this case unlike that found for QWs, NWs and QDs where the quantum confinements are 1D, 2D and 3D respectively. Consequently, the crossing of the Fermi level by the totally quantized levels in this case would have much greater impact on the redistribution of the carriers among the allowed levels, as compared to that found for QWs, NWs and QDs respectively. It is the band structure which changes in a fundamental way and consequently all the physical properties of all the electronic materials changes radically leading to new physical concepts. Section 12.4 contains 12 open research problems, which form the integral part of this chapter.