Native point defects in HgCdTe infrared detector material: Identifying deep centers from first principles
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arXiv
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| Autores principales: | , , , |
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| Formato: | Preprint |
| Publicado: |
2023
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| _version_ | 1866929274467909632 |
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| author | Chen, Wei Rignanese, Gian-Marco Liu, Jifeng Hautier, Geoffroy |
| author_facet | Chen, Wei Rignanese, Gian-Marco Liu, Jifeng Hautier, Geoffroy |
| contents | We investigate the native point defects in the long-wavelength infrared (LWIR) detector material Hg$_{0.75}$Cd$_{0.25}$Te using a dielectric-dependent hybrid density functional combined with spin-orbit coupling. Characterizing these point defects is essential as they are responsible for intrinsic doping and nonradiative recombination centers in the detector material. The dielectric-dependent hybrid functional allows for an accurate description of the band gap ($E_g$) for Hg$_{1-x}$Cd$_{x}$Te (MCT) over the entire compositional range, a level of accuracy challenging with standard hybrid functionals. Our comprehensive examination of the native point defects confirms that cation vacancies $V_\text{Hg(Cd)}$ are the primary sources of $p$-type conductivity in the LWIR material given their low defect formation energies and the presence of a shallow acceptor level ($-$/0) near the valence-band maximum (VBM). In addition to the shallow acceptor level, the cation vacancies exhibit a deep charge transition level (2$-$/$-$) situated near the midgap, characteristic of nonradiative recombination centers. Our results indicate that Hg interstitial could also be a deep center in the LWIR MCT through a metastable configuration under the Hg-rich growth conditions. While an isolated Te antisite does not show deep levels, the formation of $V_\text{Hg}$-Te$_\text{Hg}$ defect complex introduces a deep acceptor level within the band gap. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2311_05283 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Native point defects in HgCdTe infrared detector material: Identifying deep centers from first principles Chen, Wei Rignanese, Gian-Marco Liu, Jifeng Hautier, Geoffroy Materials Science Applied Physics Computational Physics We investigate the native point defects in the long-wavelength infrared (LWIR) detector material Hg$_{0.75}$Cd$_{0.25}$Te using a dielectric-dependent hybrid density functional combined with spin-orbit coupling. Characterizing these point defects is essential as they are responsible for intrinsic doping and nonradiative recombination centers in the detector material. The dielectric-dependent hybrid functional allows for an accurate description of the band gap ($E_g$) for Hg$_{1-x}$Cd$_{x}$Te (MCT) over the entire compositional range, a level of accuracy challenging with standard hybrid functionals. Our comprehensive examination of the native point defects confirms that cation vacancies $V_\text{Hg(Cd)}$ are the primary sources of $p$-type conductivity in the LWIR material given their low defect formation energies and the presence of a shallow acceptor level ($-$/0) near the valence-band maximum (VBM). In addition to the shallow acceptor level, the cation vacancies exhibit a deep charge transition level (2$-$/$-$) situated near the midgap, characteristic of nonradiative recombination centers. Our results indicate that Hg interstitial could also be a deep center in the LWIR MCT through a metastable configuration under the Hg-rich growth conditions. While an isolated Te antisite does not show deep levels, the formation of $V_\text{Hg}$-Te$_\text{Hg}$ defect complex introduces a deep acceptor level within the band gap. |
| title | Native point defects in HgCdTe infrared detector material: Identifying deep centers from first principles |
| topic | Materials Science Applied Physics Computational Physics |
| url | https://arxiv.org/abs/2311.05283 |