Thermal Energy Diffusion Incorporating Generalized Einstein Relation for Degenerate Semiconductors

Autor: Jang Jyegal
Jazyk: angličtina
Rok vydání: 2017
Předmět:
compound semiconductor
effective carrier temperature
Semiclassical physics
02 engineering and technology
Haynes–Shockley experiment
01 natural sciences
lcsh:Technology
lcsh:Chemistry
nonparabolic energy band
Quantum mechanics
0103 physical sciences
degenerate semiconductor
General Materials Science
Diffusion (business)
diffusion coefficient
Instrumentation
Einstein relation
lcsh:QH301-705.5
010302 applied physics
Fluid Flow and Transfer Processes
Physics
lcsh:T
Process Chemistry and Technology
Degenerate energy levels
General Engineering
Fermi energy
021001 nanoscience & nanotechnology
Condensed Matter::Mesoscopic Systems and Quantum Hall Effect
lcsh:QC1-999
Computer Science Applications
Degenerate semiconductor
lcsh:Biology (General)
lcsh:QD1-999
lcsh:TA1-2040
Kinetic theory of gases
0210 nano-technology
lcsh:Engineering (General). Civil engineering (General)
lcsh:Physics
Zdroj: Applied Sciences, Vol 7, Iss 8, p 773 (2017)
Applied Sciences; Volume 7; Issue 8; Pages: 773
ISSN: 2076-3417
Popis: The currently used generalized Einstein relation for degenerate semiconductors with isotropic nonparabolic energy bands produces physically improper results, as well as losing numerical accuracy for large values of nonparabolicity parameters at room temperature. Therefore, a new generalized Einstein relation (a macroscopic equation and a formula) is derived from the semiclassical momentum balance equation based on a drift-diffusion approximation, by introducing a new concept of the effective temperature of a carrier gas for generalization of the classical kinetic theory for nonideal gases of carriers in semiconductors. The proposed formula takes into account the carrier thermal energy diffusion effect completely, so that it can accurately reflect the effect of band nonparabolicity on the ratio of the diffusion coefficient to the mobility for carriers in degenerate semiconductors. From the results evaluated with the formula, new and critically important nonparabolicity effects are observed. It is shown that the new generalized Einstein relation is valid for applied electrical fields of the full linear regime. In addition, useful figures are also presented, from which the ratio of the diffusion coefficient to mobility, as well as the Fermi energy, can be easily determined from the electron concentration, or doping density, for a given semiconductor material.
Databáze: OpenAIRE