Electrical and interface characteristics of nanocrystalline n-Zn0.5Cd0.5S/p-Cu2S heterojunction structure prepared by dip coating

Nanocrystalline of n-Zn_0.5Cd_0.5S/p-Cu₂S heterojunctions were successfully prepared by the dip coating method. The surface morphology and the composition analysis were made by scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) technique, respectively. Temperature dependent current–voltage characteristics of the heterojunctions were measured in the temperature range 300–400 K with a step of 25 K. The current–voltage (I–V) characteristics exhibit electrical rectification behavior. The zero bias barrier height (Φ_B0) and the ideality factor (n) are affected by temperature. Interface states at the n-Zn_0.5Cd_0.5S/p-Cu₂S heterojunction play a crucial role in determining the electrical characteristics of the heterojunction. The high value of n can be ascribed to the presence of an interfacial layer. The energy distribution profile of the density of interface states (N_ss) was extracted from the forward bias I–V measurements using the width of the depletion region deduced from the capacitance -voltage characteristics at high frequency (1MHz).