Development of SnSe thin films through selenization of sputtered Sn-metal films

摘要

Tin monoselenide (SnSe) thin films with thickness in the range of 0.72-1.00 mu m were prepared by the two-stage process (metallization by sputtering + selenization by rapid thermal annealing) using Sn target and selenium powder at different selenization temperatures in the range of 300-450 degrees C. The formation of single-phase orthorhombic(OR)-SnSe films at >= 400 degrees C was observed, whereas the secondary phase of SnSe2 in addition to OR-SnSe was formed when the films selenized at <= 350 degrees C. The single-phase OR-SnSe films exhibited Raman modes at 33 cm(-1), 71 cm(-1), 108 cm(-1), 130 cm(-1), and 151 cm(-1). The crystallinity and grain size of the OR-SnSe films were improved with increasing of selenization temperature. The tin films selenized at 400 degrees C showed the composition ratio of Se/Sn = 0.99, the direct bandgap energy of 1.2 eV, and the p-type conductivity with electrical resistivity of 12.71 omega cm, the mobility of 2.03 cm(2) V-1 s(-1), and carrier concentration of 2.42 x 10(17) cm(-3). The above opto-electronic properties of single-phase OR-SnSe films selenized at 400 degrees C indicated that these films could be used to attain good device efficiency of solar cells.