Enhanced Optical Response of Zinc-Doped Tin Disulfide Layered Crystals Grown with the Chemical Vapor Transport Method.

Tin disulfide (SnS) is a promising semiconductor for use in nanoelectronics and optoelectronics. Doping plays an essential role in SnS applications, because it can increase the functionality of SnS by tuning its original properties. In this study, the effect of zinc (Zn) doping on the photoelectric characteristics of SnS crystals was explored. The chemical vapor transport method was adopted to grow pristine and Zn-doped SnS crystals. Scanning electron microscopy images indicated that the grown SnS crystals were layered materials. The ratio of the normalized photocurrent of the Zn-doped specimen to that of the pristine specimen increased with an increasing illumination frequency, reaching approximately five at 10 Hz. Time-resolved photocurrent measurements revealed that the Zn-doped specimen had shorter rise and fall times and a higher current amplitude than the pristine specimen. The photoresponsivity of the specimens increased with an increasing bias voltage or decreasing laser power. The Zn-doped SnS crystals had 7.18 and 3.44 times higher photoresponsivity, respectively, than the pristine crystals at a bias voltage of 20 V and a laser power of 4 × 10 W. The experimental results of this study indicate that Zn doping markedly enhances the optical response of SnS layered crystals.