Shallow and Deep States of Beryllium Acceptor in GaN: Why Photoluminescence Experiments Do Not Reveal Small Polarons for Defects in Semiconductors
| Autor: | M. Vorobiov, Michael A. Reshchikov, O. Andrieiev, T. H. Myers, Denis Demchenko |
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| Rok vydání: | 2020 |
| Předmět: |
Photoluminescence
Materials science Condensed matter physics Dopant business.industry General Physics and Astronomy chemistry.chemical_element Polaron 01 natural sciences Acceptor Condensed Matter::Materials Science Semiconductor chemistry 0103 physical sciences Valence band Density functional theory Beryllium 010306 general physics business |
| Zdroj: | Physical review letters. 126(2) |
| ISSN: | 1079-7114 |
| Popis: | Currently, only one shallow acceptor (Mg) has been discovered in GaN. Here, using photoluminescence (PL) measurements combined with hybrid density functional theory, we demonstrate that a shallow effective-mass state also exists for the ${\mathrm{Be}}_{\mathrm{Ga}}$ acceptor. A PL band with a maximum at 3.38 eV reveals a shallow ${\mathrm{Be}}_{\mathrm{Ga}}$ acceptor level at $113\ifmmode\pm\else\textpm\fi{}5\text{ }\text{ }\mathrm{meV}$ above the valence band, which is the lowest value among any dopants in GaN reported to date. Calculations suggest that the ${\mathrm{Be}}_{\mathrm{Ga}}$ is a dual-nature acceptor with the ``bright'' shallow state responsible for the 3.38 eV PL band, and the ``dark,'' strongly localized small polaronic state with a significantly lower hole capture efficiency. |
| Databáze: | OpenAIRE |
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