Simple theoretical analysis of the effective electron mass in semiconductor nanowires

In this paper we study the effective electron mass (EEM) in Nano wires (NWs) of nonlinear optical materials on the basis of newly formulated electron dispersion relation by considering all types of anisotropies of the energy band constants within the framework of k . p formalism. The results for NWs of III-V, ternary and quaternary semiconductors form special cases of our generalized analysis. We have also investigated the EEM in NWs of Bi, IV-VI, stressed Kane type materials, Ge, GaSb and Bi2Te3 by formulating the appropriate 1D dispersion law in each case by considering the influence of energy band constants in the respective cases. It has been found that the 1D EEM in nonlinear optical materials depend on the size quantum numbers and Fermi energy due to the anisotropic spin orbit splitting constant and the crystal field splitting respectively. The 1D EEM is Bi, IV-VI, stressed Kane type semiconductors and Ge also depends on both the Fermi energy and the size quantum numbers which are the characteristic features of such NWs. The EEM increases with increase in concentration and decreasing film thickness and for ternary and quaternary compounds the EEM increases with increase in alloy composition. Under certain special conditions all the results for all the materials get simplified into the well known parabolic energy bands and thus confirming the compatibility test

On the field emission from quantum wires of non-parabolic semiconductors: Simplified theory and relative assessment

An attempt is made to present a simplified theoretical formulation of the Fowler-Nordheim field emission (FNFE) in quantum wires (Qws) of non-linear optical materials on the basis of a newly formulated electron dispersion law by considering various types of anisotropies of the energy band constants within the framework of k.p formalism. We also study FNFE from Qws of III–V, II–VI and Bismuth by using the appropriate band models. Taking Qws of CdGeAs2, InAs, InSb, GaAs, Hg1−x Cd x Te and In1−x Ga x AsP1−y lattice matched to InP, CdS and Bi as examples, we observe that, the FNFE increases with increasing film thickness due to the existence van- Hove singularity and the magnitude of the quantum jumps are not of same height indicating the signature of the band structure of the material concerned. The appearance of the humps of the respective curves is due to the redistribution of the electrons among the quantized energy levels when the quantum numbers corresponding to the highest occupied level changes from one fixed value to the others. Although the field current varies in various manners with all the variables in all the cases as evident from all the curves, the rates of variations are totally band-structure dependent. All the results as derived in this paper get transformed in to the well known Fowler-Nordheim formula under certain limiting conditions, and thus confirming the compatibility test

Seebeck coefficient in quantum dots and quantum dot super lattices of heavily doped semiconductors under large magnetic field

In this chapter, an attempt is made to study the Seebeck coefficient under large magnetic field (S) in quantum dots of heavily doped nonlinear optical, III-V, II-VI, GaP, Ge, Te, PtSb2, II-V, GaSb, stressed materials, IV-VI, Lead Germanium Telluride, Zinc and Cadmium diphosphides and Bi2Te3 on the basis of newly formulated carrier dispersion laws respectively. We have also investigated the S in heavily doped III-V,IIVI, IV-VI, HgTe/CdTe and strained layer Quantum Dot Superlattices (QDSL) with graded interfaces together with the effective mass superlattices of the afore mentioned materials by formulating new carrier energy spectra. It has been found that the S for the said heavily doped quantum dots and QDSL oscillate with increasing thickness and changes with increasing electron concentration in various manners for all types of superlattices with two entirely different signatures of quantization as appropriate in respective cases of the aforementioned quantized structures. © 2013 by Nova Science Publishers, Inc. All rights reserved

Influence of crossed electric and quantizing magnetic fields on the Einstein relation in nonlinear optical, optoelectronic and related materials: Simplified theory, relative comparison and suggestion for experimental determination

An attempt is made to study the Einstein relation for the diffusivity-to-mobility ratio (DMR) under crossed fields' configuration in nonlinear optical materials on the basis of a newly formulated electron dispersion law by incorporating the crystal field in the Hamiltonian and including the anisotropies of the effective electron mass and the spin-orbit splitting constants within the framework of kp formalisms. The corresponding results for III-V, ternary and quaternary compounds form a special case of our generalized analysis. The DMR has also been investigated for II-VI and stressed materials on the basis of various appropriate dispersion relations. We have considered n-CdGeAs2, n-Hg1-xCdxTe, n-In1-xGaxAsyP1-y lattice matched to InP, p-CdS and stressed n-InSb materials as examples. The DMR also increases with increasing electric field and the natures of oscillations are totally band structure dependent with different numerical values. It has been observed that the DMR exhibits oscillatory dependences with inverse quantizing magnetic field and carrier degeneracy due to the Subhnikov-de Haas effect. An experimental method of determining the DMR for degenerate materials in the present case has been suggested. (C) 2010 Elsevier B.V. All rights reserved