In the last few years intense efforts have been devoted to the growth and characterization of semiconductor nanostrucutures. In particular, quantum dots of CdTe grown by hot wall epitaxy on Si(111) substrates constitute a very interesting example. CdTe/Si systems follow the Volmer-Weber growth mode with nucleation of 3D CdTe islands on the Si substrate even for less than one monolayer of evaporated material. In the present work, we proposed a simple one-dimension model to reproduce a very peculiar behavior observed in the quantum dot height and size distributions at distinct temperatures. The model, which includes CdTe deposition, diffusion, and revaporization, qualitatively reproduces these distributions. Moreover, the width distributions suggest a transition from Stranski-Krastanow growth mode at lower temperatures to Volmer-Weber growth mode at higher temperatures.

Using high quality epitaxial layers, we have obtained direct evidence of the band inversion in the Pb1-xSn xTe system .The samples, covering the whole composition range, were grown by molecular beam epitaxy on (111)BaF2 substrates. A minimumin the resistivity as a function of temperature was observed for all samples with Sn composition 0.35 <= x <= 0.70. In the same samples and at the same temperature, temperature dependent optical transmission measurements have revealed a change in signal of the energy gap temperature derivative, a direct evidence of the band inversion. However, the temperature for which the inversion occurs is not the one expected by the band inversion model. This discrepancy is supposed to be due to the Burstein-Moss shift caused by the relatively high hole concentration observed in these samples.