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Title: Non-radiative carrier recombination enhanced by two-level process: A first-principles study

In this study, non-radiative recombination plays an important role in the performance of optoelectronic semiconductor devices such as solar cells and light-emitting diodes. Most textbook examples assume that the recombination process occurs through a single defect level, where one electron and one hole are captured and recombined. Based on this simple picture, conventional wisdom is that only defect levels near the center of the bandgap can be effective recombination centers. Here, we present a new two-level recombination mechanism: first, one type of carrier is captured through a defect level forming a metastable state; then the local defect configuration rapidly changes to a stable state, where the other type of carrier is captured and recombined through another defect level. This novel mechanism is applied to the recombination center Te2+cd in CdTe. We show that this two-level process can significantly increase the recombination rate (by three orders of magnitude) in agreement with experiments. We expect that this two-level recombination process can exist in a wide range of semiconductors, so its effect should be carefully examined in characterizing optoelectronic materials.
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Chinese Academy of Science, Suzhou (China)
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  4. Beijing Computational Science Research Center, Beijing (China)
Publication Date:
OSTI Identifier:
1239645
Report Number(s):
NREL/JA--5K00-65022
Journal ID: ISSN 2045-2322
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 6; Related Information: Scientific Reports; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
NREL (National Renewable Energy Laboratory (NREL), Golden, CO (United States))
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS two-level recombination; theory; CdTe