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Title: Multi-phonon-assisted absorption and emission in semiconductors and its potential for laser refrigeration

Laser cooling of semiconductors has been an elusive goal for many years, and while attempts to cool the narrow gap semiconductors such as GaAs are yet to succeed, recently, net cooling has been attained in a wider gap CdS. This raises the question of whether wider gap semiconductors with higher phonon energies and stronger electron-phonon coupling are better suitable for laser cooling. In this work, we develop a straightforward theory of phonon-assisted absorption and photoluminescence of semiconductors that involves more than one phonon and use to examine wide gap materials, such as GaN and CdS and compare them with GaAs. The results indicate that while strong electron-phonon coupling in both GaN and CdS definitely improves the prospects of laser cooling, large phonon energy in GaN may be a limitation, which makes CdS a better prospect for laser cooling.
Authors:
 [1]
  1. Johns Hopkins University, Baltimore, Maryland 21208 (United States)
Publication Date:
OSTI Identifier:
22300062
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; CADMIUM SULFIDES; ELECTRON-PHONON COUPLING; GALLIUM ARSENIDES; GALLIUM NITRIDES; LASERS; PHONONS; PHOTOLUMINESCENCE; REFRIGERATION; SEMICONDUCTOR MATERIALS