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Title: Combining steady-state photo-capacitance spectra with first-principles calculations: the case of Fe and Ti in β-Ga2O3

Journal Article · · New Journal of Physics

In this study, we demonstrate an approach to identify defects in wide band gap semiconductors by comparing accumulatively-recorded derivative steady-state photo-capacitance (SSPC) spectra to simulations using results from first-principles calculations. Specifically, we present a method to simulate SSPC spectra which adopts inputs both from first-principles calculations and the experimental conditions. The applicability of the developed method is demonstrated using the cases of subsitutional Fe (FeGa) and Ti (TiGa) defects in β-Ga2O3. Using deep-level transient spectroscopy, we identify defect levels associated with $${\mathrm{Fe}}_{\text{GaI}}^{0/-}$$ (E A = 0.66 eV), $${\mathrm{Fe}}_{\text{GaII}}^{0/-}$$ (E A = 0.79 eV) and $${\mathrm{Ti}}_{\text{GaII}}^{+/\mathrm{0}}$$ (E A = 1.03 eV) in the β-Ga2O3 samples studied here. Accumulatively-recorded SSPC spectra reveal several defect levels labeled $${T}_{\mathrm{1}}^{\mathrm{E}\mathrm{F}\mathrm{G}}$$–$${T}_{\mathrm{6}}^{\mathrm{E}\mathrm{F}\mathrm{G}}$$ with onsets for optical absorption between 1.5 eV and 4.3 eV. The signature $${T}_{\mathrm{1}}^{\mathrm{E}\mathrm{F}\mathrm{G}}$$ consists of several overlapping defect signatures, and is identified as being related to $${\mathrm{Fe}}_{\text{GaI}}^{0/-}$$, $${\mathrm{Fe}}_{\text{GaII}}^{0/-}$$ and $${\mathrm{Ti}}_{\text{GaII}}^{+/\mathrm{0}}$$ by comparing measured and simulated accumulatively-recorded derivative SSPC spectra.

Research Organization:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Advanced Manufacturing Office; Research Council of Norway
Grant/Contract Number:
AC52-07NA27344; 251131
OSTI ID:
1634857
Alternate ID(s):
OSTI ID: 1668493
Report Number(s):
LLNL-JRNL-806785; 1011256
Journal Information:
New Journal of Physics, Vol. 22, Issue 6; ISSN 1367-2630
Publisher:
IOP PublishingCopyright Statement
Country of Publication:
United States
Language:
English

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Figures / Tables (7)