Synthesis of submillimeter SnSexS2−x (0 < x < 1) two-dimensional alloy and photoinduced reversible transformation between Schottky and Ohmic contact behaviors in devices. Issue 18 (26th April 2018)

• Record Type: Journal Article
• Authors: Li, Yongtao; Xiao, Wenbo; Chen, Guangfu; Dong, Huafeng; Wang, Xiaoting; Feng, Tiantian; Huang, Le; Li, Jingbo
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 18(2018)
• Page Start: 4985
• Page End: 4993
• Publication Date: 2018-04-26
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c7tc05936a
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : Large-area SnSe x S2− x single crystals were synthesized via CVD technique. Reversible switching between Schottky and Ohmic contact manner was achieved by the OFF/ON states of incident light. Abstract : The large-scale controllable synthesis of high-quality alloyed semiconductors with a precise composition and electronic modulation is of great importance for their application in electronics and optoelectronics. Here, we demonstrate the direct synthesis of two-dimensional SnSe x S2− x alloy via the chemical vapor deposition (CVD) technique. The size of single-crystal flakes could reach up to 750 μm, ten times larger than the previously reported CVD grown SnS2 and SnSe2 . The morphology of the atmospheric pressure CVD grown SnSe x S2− x flakes revealed an evolution from semi-hexagon to semi-circle as the content of Se atoms increased, while the low-pressure CVD alloyed flakes kept a constant semi-hexagon shape. UV-visible spectroscopy and PL measurement revealed adjustability of bands in the alloy flakes, where a higher Se atom content caused a narrower band gap. The SnSe x S2− x devices demonstrated a high I light / I dark ratio under switching between light and dark, whose rise and fall times were just 225.9 μs and 646.2 μs, respectively. More importantly, the devices showed Schottky-contact behaviour under dark conditions, which changed to Ohmic under illumination, leading to a tunable I light / I dark ratio controlled by the bias voltage between drain and source electrodes. This work helps the large-area growth technique and unique electrical property improvement of two-dimensional alloys to get closer to practical applications.