Electron traps in CdS single crystals obtained by admittance spectroscopy on the hetero- and Schottky junctions

The electron trap parameters in semiconducting CdS single crystals were obtained by admittance spectroscopy on its hetero- and Schottky junctions, and the trap depths obtained were 0.065, 0.09, 0.15 0.20, and 0.40 eV. The capture cross-section of the shallowest trap on the Cd-face of the crystals was about 10⁻¹⁹ cm², one order smaller than that of the bulk crystal. The resolving power of the employed method was about 50 meV to distinguish the two traps with different depths. The results of the computer simulation of this method suggested that the trap can be determined when the trap density is at least one order lower than the donor density. The calculated density of the each trap was 1×10¹⁵ cm⁻³ for the shallowest trap and 2×10¹⁶ cm⁻³ for the remaining traps, respectively.