Quantum confinement effects on the photoluminescence spectra of CdTe nanocrystallites

Quantum size and semiconductor volume fraction effects on the intensity, line width and position of photoluminescence (PL) peaks from CdTe nanocrystallites have been measured. CdTe-glass composite thin films were grown by using a sequential rf-magnetron sputtering process. Postdeposition heat treatments were used to produce average crystallite sizes between 1.2 and 16 nm. The PL spectra consist of single, broad peaks that undergo larger blue shifts with decreasing crystallite sizes. The PL signal degrades with increasing nanocrystallite size and is quenched at the higher semiconductor volume fractions. The spectral characteristics of the clusters are discussed in terms of the electron-hole pair and the effect of surface states.