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Title: First-principles characterization of native-defect-related optical transitions in ZnO

We investigate the electrical and optical properties of oxygen vacancies (VO), zinc vacancies (V Zn), hydrogenated V Zn, and isolated dangling bonds in ZnO using hybrid functional calculations. While the formation energy of V O is high in n-type ZnO, indicating that this center is unlikely to form, our results for optical absorption signals associated with V O are consistent with those observed in irradiated samples, and give rise to emission with a peak at less than 1 eV. Under realistic growth conditions, we find that VZn is the lowest-energy native defect in n-type ZnO, acting as an acceptor that is likely to compensate donor doping. Turning to optical transitions, we first examine N O as a case study, since N-related transitions have been identified in experiments on ZnO. Here, we also examine how hydrogen, often unintentionally present in ZnO, forms stable complexes with V Zn and modifies its optical properties. Compared with isolated V Zn, V Zn-H complexes have charge-state transition levels lower in the band gap as well as have lower formation energies. These complexes also lead to characteristic vibrational frequencies which compare favorably with experiment. Oxygen dangling bonds show behavior mostly consistent with V Zn, while zincmore » dangling bonds give rise to transition levels near the ZnO conduction-band minimum and emission peaking near 2.4 eV. Lastly, we discuss our results in view of the available experimental literature.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ; ORCiD logo [3]
  1. Naval Research Lab. (NRL), Washington, DC (United States). Center for Computational Materials Science
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Univ. of California, Santa Barbara, CA (United States). Dept. of Materials
  4. Univ. of Delaware, Newark, DE (United States). Dept. of Materials Science and Engineering
Publication Date:
Report Number(s):
LLNL-JRNL-735588
Journal ID: ISSN 0021-8979
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 122; Journal Issue: 3; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE; US Army Research Office (ARO); National Science Foundation (NSF); US Department of the Navy, Office of Naval Research (ONR)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Chemical compounds; Metalloids; Chemical bonds; Band gap; Exchange correlation functionals
OSTI Identifier:
1418932