Large and persistent photoconductivity due to hole-hole correlation in CdS
Large and persistent photoconductivity (LPPC) in semiconductors is due to the trapping of photogenerated minority carriers at crystal defects. Theory has suggested that anion vacancies in II-VI semiconductors are responsible for LPPC due to negative-U behavior, whereby two minority carriers become k...
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| Format: | Article |
| Language: | English |
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American Physical Society
2018
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| Online Access: | http://hdl.handle.net/1721.1/117334 https://orcid.org/0000-0001-6507-5140 https://orcid.org/0000-0003-3116-6719 |
| _version_ | 1811078972275949568 |
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| author | Yin, Han Akey, Austin Jaramillo, Rafael |
| author2 | Massachusetts Institute of Technology. Department of Materials Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Materials Science and Engineering Yin, Han Akey, Austin Jaramillo, Rafael |
| author_sort | Yin, Han |
| collection | MIT |
| description | Large and persistent photoconductivity (LPPC) in semiconductors is due to the trapping of photogenerated minority carriers at crystal defects. Theory has suggested that anion vacancies in II-VI semiconductors are responsible for LPPC due to negative-U behavior, whereby two minority carriers become kinetically trapped by lattice relaxation following photoexcitation. By performing a detailed analysis of photoconductivity in CdS, we provide experimental support for this negative-U model of LPPC. We also show that LPPC is correlated with sulfur deficiency. We use this understanding to vary the photoconductivity of CdS films over nine orders of magnitude, and vary the LPPC characteristic decay time from seconds to 10⁴s by controlling the activities of Cd²⁺ and S²⁻ ions during chemical bath deposition. We suggest a screening method to identify other materials with long-lived, nonequilibrium, photoexcited states based on the results of ground-state calculations of atomic rearrangements following defect redox reactions, with a conceptual connection to polaron formation. |
| first_indexed | 2024-09-23T11:07:49Z |
| format | Article |
| id | mit-1721.1/117334 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T11:07:49Z |
| publishDate | 2018 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/1173342022-10-01T01:28:31Z Large and persistent photoconductivity due to hole-hole correlation in CdS Yin, Han Akey, Austin Jaramillo, Rafael Massachusetts Institute of Technology. Department of Materials Science and Engineering Massachusetts Institute of Technology. Department of Mechanical Engineering Yin, Han Jaramillo, Rafael Large and persistent photoconductivity (LPPC) in semiconductors is due to the trapping of photogenerated minority carriers at crystal defects. Theory has suggested that anion vacancies in II-VI semiconductors are responsible for LPPC due to negative-U behavior, whereby two minority carriers become kinetically trapped by lattice relaxation following photoexcitation. By performing a detailed analysis of photoconductivity in CdS, we provide experimental support for this negative-U model of LPPC. We also show that LPPC is correlated with sulfur deficiency. We use this understanding to vary the photoconductivity of CdS films over nine orders of magnitude, and vary the LPPC characteristic decay time from seconds to 10⁴s by controlling the activities of Cd²⁺ and S²⁻ ions during chemical bath deposition. We suggest a screening method to identify other materials with long-lived, nonequilibrium, photoexcited states based on the results of ground-state calculations of atomic rearrangements following defect redox reactions, with a conceptual connection to polaron formation. United States. Office of Naval Research (Grant N00014-17-1-2661) 2018-08-13T15:42:52Z 2018-08-13T15:42:52Z 2018-08 2017-04 2018-08-03T18:00:12Z Article http://purl.org/eprint/type/JournalArticle 2475-9953 http://hdl.handle.net/1721.1/117334 Yin, Han et al. "Large and persistent photoconductivity due to hole-hole correlation in CdS." Physical Review Materials 2, 8 (August 2018): 084602 © 2018 American Physical Society https://orcid.org/0000-0001-6507-5140 https://orcid.org/0000-0003-3116-6719 en http://dx.doi.org/10.1103/PhysRevMaterials.2.084602 Physical Review Materials Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. American Physical Society application/pdf American Physical Society American Physical Society |
| spellingShingle | Yin, Han Akey, Austin Jaramillo, Rafael Large and persistent photoconductivity due to hole-hole correlation in CdS |
| title | Large and persistent photoconductivity due to hole-hole correlation in CdS |
| title_full | Large and persistent photoconductivity due to hole-hole correlation in CdS |
| title_fullStr | Large and persistent photoconductivity due to hole-hole correlation in CdS |
| title_full_unstemmed | Large and persistent photoconductivity due to hole-hole correlation in CdS |
| title_short | Large and persistent photoconductivity due to hole-hole correlation in CdS |
| title_sort | large and persistent photoconductivity due to hole hole correlation in cds |
| url | http://hdl.handle.net/1721.1/117334 https://orcid.org/0000-0001-6507-5140 https://orcid.org/0000-0003-3116-6719 |
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