Ultra-high performance flexible piezopotential gated In1−xSnxSe phototransistorElectronic supplementary information (ESI) available. See DOI: 10.1039/c8nr05234d

• Main Authors: Paul Inbaraj, Christy Roshini, Mathew, Roshan Jesus, Haider, Golam, Chen, Tzu-Pei, Ulaganathan, Rajesh Kumar, Sankar, Raman, Bera, Krishna Prasad, Liao, Yu-Ming, Kataria, Monika, Lin, Hung-I, Chou, Fang Cheng, Chen, Yit-Tsong, Lee, Chih-Hao, Chen, Yang-Fang
• Format: Journal Article
• Published: 11.10.2018
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c8nr05234d

Flexible optoelectronic devices facilitated by the piezotronic effect have important applications in the near future in many different fields ranging from solid-state lighting to biomedicine. Two-dimensional materials possessing extraordinary mechanical strength and semiconducting properties are essential for realizing nanopiezotronics and piezo-phototronics. Here, we report the first demonstration of piezo-phototronic properties in In 1− x Sn x Se flexible devices by applying systematic mechanical strain under photoexcitation. Interestingly, we discover that the dark current and photocurrent are increased by five times under a bending strain of 2.7% with a maximum photoresponsivity of 1037 AW −1 . In addition, the device can act as a strain sensor with a strain sensitivity up to 206. Based on these values, the device outperforms the same class of devices in two-dimensional materials. The underlying mechanism responsible for the discovered behavior can be interpreted in terms of piezoelectric potential gating, allowing the device to perform like a phototransistor. The strain-induced gate voltage assists in the efficient separation of photogenerated charge carriers and enhances the mobility of In 1− x Sn x Se, resulting in good performance on a freeform surface. Thus, our multifunctional device is useful for the development of a variety of advanced applications and will help meet the demand of emerging technologies. Strain tunable flexible InSnSe phototransistor holds promise for the future piezophototronics.