Effect of doping on transport properties of nanocrystalline CdSe thin film

• The dark and photoconductivity are measured as a function of temperature.
• The photocurrent is found to dominate by bimolecular nature of recombination.
• We have presented a successful study of the application of the SSPG techniques.
• The minority carrier diffusion length has been found to decrease with doping.

The effect of In and Zn doping on the transport properties of nanocrystalline CdSe thin films has been investigated. Thin films are prepared by the physical vapor deposition technique. The films crystallize in a hexagonal structure with spherical particles of nanometer range having different sizes and uniformly distributed all over the surface of the substrates. The experimental data of DC electrical conductivity measurements suggest that the conduction in the high temperature range occurs in the extended states while conduction in the low temperature range takes place through a variable range hopping. The bimolecular recombination nature of the thin films has been revealed by the photoconductivity illumination dependence. The mobility lifetime product and minority carrier diffusion length of thin films have been investigated by the time of flight and steady state photocarrier grating technique respectively. The values of minority carrier diffusion length are found to be 184 nm, 107 nm and 103 nm for nc-CdSe, nc-CdSe:In and nc-CdSe:Zn thin films, respectively.