Enhanced electrical conductivity and photoconductive properties of Sn-doped Sb2Se3 crystals

Abstract

Sb₂Se₃ is a highly interesting semiconductor with high absorption coefficient in the visible range and is composed of non-toxic and earth-abundant elements. To overcome the challenge of intrinsic low electrical conductivity of Sb₂Se₃ crystals, tin-doped (Sn_xSb_1−x)₂Se₃ semiconductors (x = 0.00, 0.03, 0.05, 0.07 and 0.10) have been synthesized by a conventional melt-quenching method in a vacuum sealed silica tube. With increasing Sn doping concentration, the (Sn_xSb_1−x)₂Se₃ crystals exhibited a great improvement in electrical conductivity by several orders of magnitude thanks to the great increase of carrier concentration reaching almost 2 × 10¹⁶ cm⁻³. Compared to undoped Sb₂Se₃, the dark current density of a representative (Sn_0.10Sb_0.90)₂Se₃ increased by approximately 10 times and the photocurrent density with essentially visible illumination increased by approximately 14 times. In addition, the doped sample showed a faster, reversible and stable photoresponse. These excellent performances combined with a simple and easily scalable synthesis method pave the way for using this semiconductor for highly efficient photoelectric devices.