Enhanced electrical conductivity and photoconductive properties of Sn-doped Sb2Se3 crystals†
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 (SnxSb1−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 (SnxSb1−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 (Sn0.10Sb0.90)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.