Abstract
Ternary layered III–III–VI2-type metal chalcogenides are a comparatively new group of semiconductors and have attracted strong interest due to their distinct optical and electrical properties in view of potential applications in nonlinear optical, acousto-optical and optoelectronic devices. Here, we report on the fabrication of two-terminal phototransistors based on ultrathin direct-bandgap TlGaSe2 sheets for the first time. Devices exhibit typical p-type conducting behaviors with current on/off ratio of ~102 and gate-tunable transport characteristics. The photocurrent presents stable and reproducible response for various wavelengths of light from ultraviolet (UV) to near-infrared region, confirming the broadband photodetection capability. Photoresponsive behavior of ultrathin TlGaSe2 phototransistors can be modulated by the incident optical power density or wavelength, as well as bias or back-gate voltages. Owing to the presence of direct bandgap, devices possess high photoresponsivity (270 mA W−1) under white light in vacuum, and it is higher than that of single-layer MoS2 phototransistor and graphene photodetectors, accompanying by a fast response time of ~0.2 s. Our studies introduce ternary alloy monochalcogenides phototransistors, and expand the library of ultrathin flexible semiconductors.
Original language | English (US) |
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Article number | 035021 |
Journal | 2D Materials |
Volume | 4 |
Issue number | 3 |
DOIs | |
State | Published - Sep 2017 |
Keywords
- 2D phototransistors
- Broadband response
- Direct bandgap
- Ternary semiconductor
- TlGaSe2
ASJC Scopus subject areas
- General Chemistry
- General Materials Science
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering