Deep level transient spectroscopy measurement on tin-doped n-indium selenide

Abstract

Deep level transient spectroscopy measurements in indium selenide samples doped with different amounts of tin are reported. Three tin-related electron traps have been detected with activation energies for emission of 56, 74, and 110 meV. The capture cross-section has also been measured and it is very low and weakly dependent on temperature for the 74 and 110 meV deep levels that are attributed to electron trap states related to ionized acceptor centers. For the 56 meV level the apparent capture cross-section shows an activated temperature dependence with an activation energy of 35 meV, which yields an ionization energy of 21 meV for the related level, which corresponds to the tin-related shallow donor. That behaviour is interpreted through the presence in InSe of stacking-fault-related barriers. When one of these barriers is swept by the depletion zone edge during the emptying or filling pulses, electrons must overcome that barrier in order to be emitted or captured, which results in a reduction of the effective capture and emission rates of shallow donors which thus become observable through capacitance transients.