Silicon-based two-dimensional chalcogenide of p-type semiconducting silicon telluride nanosheets for ultrahigh sensitive photodetector applications

Two-dimensional (2D) materials have attracted significant attention in recent years owing to their exotic properties. Semiconducting p-type 2D crystals are crucial to the construction of versatile p–n junction-based nanoelectronic devices, and promising future optoelectronic applications. Herein, we reported the growth of high-quality p-type silicon telluride (Si2Te3) single crystals using the chemical vapor transport (CVT) technique. Few layered Si2Te3 nanosheets were obtained by mechanical exfoliation and used to fabricate a phototransistor device under a rigid silicon substrate. The Si2Te3 nanosheet-based transistor exhibits an outstanding device performance, such as a high photoresponsivity of approximately 1396 A W−1 and a larger specific detectivity of approximately 2.52 × 1012 Jones at a wavelength of 633 nm. The values obtained using the Si2Te3 single crystal are remarkably superior to those obtained for the other chalcogenide 2D crystals, such as Bi2Te3 and Sb2Te3. In addition, the normalized gain value of approximately 2.74 × 10−4 V−1 cm2 achieved using this field-effect transistor (FET) device is several orders higher than those of the other 2D single crystal-based FET devices. Our results suggest that the Si2Te3 single crystal could be a benchmark candidate for the integration of prospective p–n junction circuits and photo-sensing applications.