Study of the light-induced metal-insulator transition in SrTiO3 by photoresistance spectroscopy
Photoresistivity and its spectral response has been systematically studied in oxygen deficient SrTiO3 single crystals for a wide range of resistivities, ρ, and carrier densities, n. At roomtemperature we have found a persistent photoresistance that gradually decreases as ρ is diminished or n is incr...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2015 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/12667 |
| Acceso en línea: | http://hdl.handle.net/11336/12667 |
| Access Level: | acceso abierto |
| Palabra clave: | Metal Insulator Transition Srtio3 Photoresistance Spectroscopy https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
| Sumario: | Photoresistivity and its spectral response has been systematically studied in oxygen deficient SrTiO3 single crystals for a wide range of resistivities, ρ, and carrier densities, n. At roomtemperature we have found a persistent photoresistance that gradually decreases as ρ is diminished or n is increased in addition to relaxation times of seconds to a few minutes suggesting that trapping of carriers is playing a major role. An analysis of the photoresistance excitation spectra shows two distinctive features that are related to the indirect gap of SrTiO3 at (3.25 ± 0.04) eV and to a direct transition at (3.40 ± 0.03) eV. The photoresistive crystals present a temperature dependent resisitivity under illumination that experiences a metal-insulator transition below T ∼ 85 K. Lowtemperature photoresistance spectrum reveals as a suitable technique to understand the origin of this transition, pointing to an enhanced efficiency of the ∼ 3.25 eV gap to promote electrons to the bottom of the conduction band. |
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