Piezoelectric and optoelectronic properties of [alpha]-In.sub.2Se.sub.3 single-crystal nanobelts synthesized by a direct selenization of In.sub.2O.sub.3

Indium selenide (In.sub.2Se.sub.3) is an attractive layered semiconductor material with promising optoelectronic and piezoelectric applications. In this work, single-crystalline [alpha]-In.sub.2Se.sub.3 nanobelts are synthesized using a catalyst-free chemical vapor deposition method through the direct selenization of In.sub.2O.sub.3 powders. The as-grown nanobelts are single crystals with high crystallinity and regular outer shapes. The piezoelectric response d.sub.33 of a 50 nm-thick [alpha]-In.sub.2Se.sub.3 nanobelt is, for the first time, determined to be approximately 1.6 pm·V.sup.-1. The photodetector using the In.sub.2Se.sub.3 nanobelts exhibits high photoresponsivity of 66.6 A·W.sup.-1 at 442 nm and high stability under an atmospheric environment. This work provides a new route for the development of [alpha]-In.sub.2Se.sub.3 nanobelts as promising candidates for low-cost, nanoscale actuators, sensors, and detectors.