Temperature-dependent optical absorption measurements and Schottky contact behavior in layered semiconductor n-type InSe(:Sn)

The layered n-InSe(:Sn) single crystal samples have been cleaved from a large crystal ingot grown from non-stoichiometric melt by the Bridgman–Stockbarger method. It has been made the absorption measurements of these samples without Schottky contact under electric fields of 0.0 and 6000 V cm 1. The band gap energy value of the InSe:Sn has been calculated as 1.36 0.01 eV (at 10 K) and 1.28 0.01 eV (at 300 K) under zero electrical field, and 1.31 0.01 eV (at 10 K) and 1.26 0.01 eV (at 300 K) under 6000 Vcm 1. The current–voltage (I–V) characteristics of Au–Ge/InSe(:Sn)/In Schottky diodes have been measured in the temperature range 80–320 K with a temperature step of 20 K. An experimental barrier height (BH) Fap value of about 0.70 0.01 eV was obtained for the Au–Ge/InSe(:Sn)/In Schottky diode at the room temperature (300 K). An abnormal decrease in the experimental BH Fb and an increase in the ideality factor n with a decrease in temperature have been explained by the barrier inhomogeneities at the metal–semiconductor interface. From the temperature-dependent I–V characteristics of the Au–Ge/InSe(:Sn)/In contact, that is, ¯Fbo and A* as 0.94 0.02 and 0.58 0.02 eV, and 27 2 and 21 1 (A/cm2 K2), respectively, have been calculated from a modified lnðI0=T2Þ q2s2s =2k2T2 versus 1/T plot for the two temperature regions. The Richardson constant values are about two times larger than the known value of 14.4 (A/cm2 K2) known for n-type InSe. Moreover, in the temperature range 80–320 K, we have also discussed whether or not the current through the junction has been connected with TFE