Optical and structural evidence of the grain-boundary influence on the disorder of polycrystalline CdTe films

A linear dependence of the band-tail parameter of absorption spectra and the full width at half maximum (FWHM) of X-ray diffraction on the reciprocal of the grain size of CdTe polycrystalline samples is obtained to present evidence of the influence of the grain boundary on disorder. The trap density was calculated using theoretical analysis. The disorder and trap distribution is gradual with a maximum in the grain boundary and diminish toward the grain inside part.