Numerical Analysis of the On-State of Diode Structures Based on Direct-Gap Semiconductors

Abstract

In this paper, a numerical onedimensional steady-stke analysis of forward-biased diode structures based on direct-gap semiconductors is presented. The model used in this study is based on numerical solution of the set of fundamental equations for semiconductors with boundary conditions on contacts. The continuity equations for electrons and holes are modified to take into account the carrier generation due to band-toband recombination radiation in the n-base and p+-emitter regions. The abrupt junctions in a p +-n-n +-structure and theoretical band-to-band recombination radiation spectra are assumed. Results of calculations on GaAs are given.

Comparison of photon recycling effect in GaAs and GaN structures

“…Probably the first completely numerical simulator, accounting for recombination radiation reabsorption effect in multijunction direct band-gap semiconductor structures, was developed by Velmre with collaborators [ 13,14 ]. The mathematical model used in this one-dimensional (1D) simulator was based on the finite difference solution of the full set of semiconductor equations in drift-diffusion approximation with boundary conditions on the terminal contacts of the structure.…”

“…The electron and hole continuity equations have been modified to take account of the carrier generation due to reabsorption of the band-to-band recombination radiation. Simulation results [ 13,14 ] of forward steady-state characteristics of GaAs p-i-n diodes demonstrated a significant role of the photon recycling on the behaviour of the power devices, especially at a high operation current level. Unfortunately, the Seidman-Choo iterative scheme [ 15 ], which was implemented in our early simulators, was not efficient at high forward currents.…”

“…Several authors have discussed that problem [ [25][26][27]. Our earlier publications [ 13,14 ] have followed mainly the approach of Kuriyama et al [ 26 ]. If monochromatic photon flux, emitted at , ′ x would be parallel to the x axis and equally distributed between two possible directions, the probability that a photon reaches coordinate x would be 2 ) ( exp u P α − = and the probability that a photon is absorbed at x in a layer…”

“…x yields the following general expression for the photon recycling generation rate pr G at an arbitrary point on the x axis in case of homogeneously doped layer with thickness w [ 14,24 ]:…”

“…In our earlier studies, numerical simulation of different GaAs device structures [ 13,14 ] or analytical approximations for carrier modified diffusion coefficients and transfer factors through the device layers were considered [ 24 ]. The pure numerical simulations usually do not reveal explicitly the important interrelations between physical quantities in a wider scale.…”