Ultrathin ternary semiconductor TlGaSe2 phototransistors with Broad-spectral response

Shengxue Yang, Minghui Wu, Hui Wang, Hui Cai, Li Huang, Chengbao Jiang, Sefaattin Tongay

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


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 languageEnglish (US)
Article number035021
Journal2D Materials
Issue number3
StatePublished - Sep 2017


  • 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


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