Parameters of Deep Traps Responsible for Dark Conductivity of ZnSe Single Crystals

V.Ya. Degodaa, G.P. Podusta, N.Yu. Pavlovab, N.V. Martynyukc aTaras Shevchenko National University of Kyiv, Physics Department, 03680 Kyiv, Ukraine bNational Pedagogical Dragomanov University, Kyiv, Ukraine cLviv Polytechnic National University, Lviv, Ukraine

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The use of ZnSe single crystals as semiconductor detectors of ionizing radiation at room temperature requires determining the nature of their dark conductivity. Studies of the current-voltage characteristics of photo- and dark conductivity as well as temperature dependence of dark conductivity allowed us to establish that dark conductivity in ZnSe crystals is due to the thermal delocalization of electrons from deep traps. Electrons fall into these deep traps due to thermal ionization of shallow donors. A method for determining the concentrations of deep traps and their occupation degree is proposed. The paper demonstrates the use of this method for high-resistance ZnSe single crystals. In these crystals, the concentrations of deep electron traps reach 1015 cm-3 and are located at around 0.6-1 eV in the band gap.

DOI:10.12693/APhysPolA.140.78 topics: dark conductivity, deep electron traps, current-voltage characteristics, ZESe single crystals