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Title: Using Superlattice Ordering to Reduce the Band Gap of Random (In,Ga)As/InP Alloys to a Target Value Via the Inverse Band Structure Approach

Abstract

Thermophotovoltaic (TPV) devices are intended to absorb photons from hot blackbody radiating objects, often requiring semiconductor absorbers with band gap of {approx_equal} 0.6 eV. The random In{sub x}Ga{sub 1-x}As alloy lattice matched (x{sub In}=0.53) to a (001) InP substrate has a low-temperature band gap of 0.8 eV, about 0.2 eV too high for a TPV absorber. Bringing the band gap down by raising the In concentration induces strain with the substrate, leading to a two-dimensional (2D) {yields} three-dimensional (3D) morphological transition occurring before band gaps suitable for TPV applications are achieved. We use the inverse band structure approach, based on a genetic algorithm and empirical pseudopotential calculations, to search for lattice-matched InAs/GaAs multiple-repeat unit structures with individual layer thicknesses lower than the critical thickness for a 2D {yields} 3D transition. Despite the fact that quantum confinement usually increases band gaps, we find a quantum superlattice structure with the required reduced gap (and a significant optical transition) that matches all target requirements. This is explained by the predominance of (potential-energy) level anticrossing effects over (kinetic) quantum confinement effects.

Authors:
;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
947869
DOE Contract Number:  
AC36-99-GO10337
Resource Type:
Journal Article
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 78; Journal Issue: 16, October 2008; Related Information: Article No. 161302(R)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALGORITHMS; ALLOYS; CONFINEMENT; GENETICS; PHOTONS; POTENTIAL ENERGY; STRAINS; SUBSTRATES; SUPERLATTICES; TARGETS; THICKNESS; Energy Sciences; Solid State Theory

Citation Formats

Piquini, P, and Zunger, A. Using Superlattice Ordering to Reduce the Band Gap of Random (In,Ga)As/InP Alloys to a Target Value Via the Inverse Band Structure Approach. United States: N. p., 2008. Web. doi:10.1103/PhysRevB.78.161302.
Piquini, P, & Zunger, A. Using Superlattice Ordering to Reduce the Band Gap of Random (In,Ga)As/InP Alloys to a Target Value Via the Inverse Band Structure Approach. United States. https://doi.org/10.1103/PhysRevB.78.161302
Piquini, P, and Zunger, A. Wed . "Using Superlattice Ordering to Reduce the Band Gap of Random (In,Ga)As/InP Alloys to a Target Value Via the Inverse Band Structure Approach". United States. https://doi.org/10.1103/PhysRevB.78.161302.
@article{osti_947869,
title = {Using Superlattice Ordering to Reduce the Band Gap of Random (In,Ga)As/InP Alloys to a Target Value Via the Inverse Band Structure Approach},
author = {Piquini, P and Zunger, A},
abstractNote = {Thermophotovoltaic (TPV) devices are intended to absorb photons from hot blackbody radiating objects, often requiring semiconductor absorbers with band gap of {approx_equal} 0.6 eV. The random In{sub x}Ga{sub 1-x}As alloy lattice matched (x{sub In}=0.53) to a (001) InP substrate has a low-temperature band gap of 0.8 eV, about 0.2 eV too high for a TPV absorber. Bringing the band gap down by raising the In concentration induces strain with the substrate, leading to a two-dimensional (2D) {yields} three-dimensional (3D) morphological transition occurring before band gaps suitable for TPV applications are achieved. We use the inverse band structure approach, based on a genetic algorithm and empirical pseudopotential calculations, to search for lattice-matched InAs/GaAs multiple-repeat unit structures with individual layer thicknesses lower than the critical thickness for a 2D {yields} 3D transition. Despite the fact that quantum confinement usually increases band gaps, we find a quantum superlattice structure with the required reduced gap (and a significant optical transition) that matches all target requirements. This is explained by the predominance of (potential-energy) level anticrossing effects over (kinetic) quantum confinement effects.},
doi = {10.1103/PhysRevB.78.161302},
url = {https://www.osti.gov/biblio/947869}, journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 16, October 2008,
volume = 78,
place = {United States},
year = {2008},
month = {10}
}