Graphene- WS2 van der Waals Hybrid Heterostructure for Photodetector and Memory Device Applications
| Autor: | Tanweer Ahmed, Arindam Ghosh, Sreemanta Mitra, Saloni Kakkar |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Graphene business.industry Physics::Optics General Physics and Astronomy Photodetector Optical power Heterojunction 02 engineering and technology Orders of magnitude (numbers) 021001 nanoscience & nanotechnology 01 natural sciences Atomic units law.invention Condensed Matter::Materials Science symbols.namesake Responsivity law 0103 physical sciences symbols Optoelectronics van der Waals force 010306 general physics 0210 nano-technology business |
| Zdroj: | Physical Review Applied. 14 |
| ISSN: | 2331-7019 |
| DOI: | 10.1103/physrevapplied.14.064029 |
| Popis: | The intriguing electronic properties of graphene and the strong light-matter interaction in layered transition-metal dichalcogenide (TMDC) make them a natural partner for hybrid devices, not only for optoelectronic device applications, but also to understand the conversion of light to electricity in this atomic scale prototype of a donor-acceptor complex. Here, we describe graphene-on-${\mathrm{WS}}_{2}$ binary heterostructure FET device, displaying gate-tunable persistent photoconductivity. Our time-dependent photovoltage relaxation experiments suggest that the charge-transfer time scale in this heterostructure is dependent on the input optical power, contrary to what is observed for the bare TMDC and is orders of magnitude slower than that observed for various other vdW hybrids. The optoelectronic responsivity of this device at low optical power is found to be as high as ${10}^{10}\phantom{\rule{0.1em}{0ex}}\mathrm{V/W}$, and thus shows the potential to be one of the most sensitive visible range photodetectors, while the gate tunability of the persistent photoconductivity can be utilized in the memory device applications. We identify that the photoresponse is the outcome of a photogating mechanism, due to the exciton dissociation under optical excitation, followed by the trapping of holes in ${\mathrm{WS}}_{2}$ and subsequent electron transfer to graphene. |
| Databáze: | OpenAIRE |
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