Electrical characterization of nanocrystalline zinc selenide thin films

Authors

• Jeewan Sharma ¹
• Deep Shikha ²
• Surya Kant Tripathi ³

1. Department of Nanotechnology, Sri Guru Granth Sahib World University
2. Ambala College of Engineering and Applied Research;Department of Physics, Maharishi Markandeshwar University
3. Department of Physics, Panjab University

Abstract

AbstractIn the present paper, we have studied the effect of photo-illumination on electrical properties of nanocrystalline ZnSe thin films. The ZnSe thin films with different grain sizes (coherently diffracting domains) have been prepared. The semiconducting material with the composition Zn25Se75 has been prepared using melt-quenching technique. Thermal evaporation technique has been used to prepare nanocrystalline ZnSe thin films on highly cleaned glass substrates at different partial pressures of Ar gas. The grain size has been controlled by the partial pressure of inert gas. The grain size has been calculated using X-ray diffraction plots. Mobility activation has been studied from the photocurrent decay curves. The effective density of states (Neff), frequency factor (S), and trap depth (E) have been calculated for all the films having different grain sizes. Three different types of trap levels have been found in these films. There is a linear distribution of traps having different energies below the conduction band. The increase in photoconductivity is explained in terms of built in potential barriers (ϕb) at the grain boundaries.

Keywords

• Trap depth
• 73.20.At
• 73.63.Bd
• 78.30.Fs
• Effective density of states
• Potential barrier