Impurity perturbation to the host band structure and recoil of the impurity state

Abstract

At sufficiently high doping levels, the impurities in a semiconductor are expected to perturb the host band structure, and the perturbed host is then expected to alter the impurity state from that of the dilute limit ͑a recoil͒. Despite many decades of studies on impurities, it has been impossible to simultaneously and accurately track the evolution of the host band structure and the impurity state. The isoelectronically doped system provides a unique opportunity to track this evolution. GaAs:N, as a prototype system, has been investigated both experimentally and theoretically for this purpose.

Photoluminescence from the nitrogen-perturbed above-bandgap states in dilute GaAs1−xNx alloys: A microphotoluminescence study

“…19 In a previous publication, 24 the calculated bandgap reductions in the dilute limit have been shown to be in excellent agreement with the experimental data. The N x level is also found to agree quite well with the generally accepted one.…”

Systematic approach for simultaneously correcting the band-gap andp−dseparation errors of common cation III-V or II-VI binaries in density functional theory calculations within a local density approximation

“…This approach has been shown to work very well, often with few meV accuracy in determining the impurity levels and alloy bandgaps. [35][36][37] However, in the past, the fitting was typically done case by case for two binaries with a common cation, for instance, GaP and GaN or GaAs and GaN, where the correction to Ga pseudopotentials were different for the two pairs.…”

“…[27][28][29][30][31][32][33][34] In certain cases, a DFT-LDA-C method can often offer very good results for the electronic structure, with accuracy comparable to that of optical spectroscopy (typically in the order of 10 meV). [35][36][37][38] Besides the electronic structure, this type approach has also been shown to yield significantly better results in calculating the ground state properties (e.g., binary formation energy). [39] However, it remains impractical to calculate more complex structures that involve more than two binaries and correct LDA errors in more than just bandgap (see more discussions later).…”

<p class="IJOPCMTitle">A study on structural and electronic properties of GaAs_1-xN_xand GaAs_1-xBi_x alloys</p>

“…In recent years, the semiconductor alloys GaAs 1-x N x and GaAs 1-x Bi x have great attention as promising materials for long wavelength optoelectronic device applications. These alloys have strong band gap tunability [1], [2] and exhibit a much greater reduction of the bandgap energy with increasing x than predicted by the linear trend of the virtual crystal approximation (VCA). The bismuth alloy GaAs 1−x Bi x is complementary to nitrides because incorporating Bi in GaAs perturbs the valence band, whereas N in GaAs perturbs the conduction band.…”