The trap density Nt and mobility-lifetime product µt in CdSe thin films are investigated combining data from thermally stimulated conductivity and photoconductivity measurements. A method of simultaneous fitting of thermally stimulated conductivity spectra is applied and four peaks at 193, 213, 230 and 258 K are resolved in the temperature range 80-270 K. Temperature dependences of the steady-state photoconductivity under excitation with strongly absorbed light (525 and 630 nm) are measured at photon fluxes of 5x1013 - 5x1015 cm-2.s-1 and temperature dependences of the exponent ? in the intensity dependence of the photoconductivity are obtained. The µt products and trap densities Nt are calculated for both kinds of light excitation. It is shown that they depend on the wavelength of the exciting light, being 2-3 times larger for excitation with ?=630 nm.
|Number of pages||4|
|Journal||Journal of Optoelectronics and Advanced Materials|
|Publication status||Published - 2007|