The effect of thermal treatment during and after growth of InGaAs/GaAs quantum dot (QD) structures was studied. Transmission electron microscopy and atomic force microscopy confirmed the presence of interacting QDs, as was expected from analysis of temperature dependence of QD photoluminescence (PL) peak. The results indicate that the effect of post-growth annealing can be similar to the effect of elevated temperature of capping layer growth. Both, these thermal treatments can lead to a similar In and Ga interdiffiusion resulting in a similar blue-shift of QD PL peak.

The effect of post-growth thermal treatment of the InAs/GaAs quantum dots is investigated in this work. The photoluminescence (PL) and transmission electron microscopy (TEM) studies of samples annealed at temperatures up to 950 degrees C are presented. A complete dissolution of QDs and substantial broadening of the wetting layer (WL) can be seen from TEM. We propose that the thermally induced modification of the WL rather than QDs can be responsible for a blue-shift and narrowing of PL peaks in structures containing InAs/GaAs QDs.

We report on the formation of low resistivity ohmic contacts to p-GaN, rc<10-4Wcm2, by increasing the concentration of the active Mg in the subcontact zone, via Zr-mediated release of hydrogen.

Microstructure and thermal stability of ZrN/ZrB2 bilayer deposited on GaN have been studied using transmission electron microscopy methods (TEM) and secondary ion mass spectrometry (SIMS). It has been demonstrated that annealing of the contact structure at 11000C in N2 atmosphere does not lead to any observable metal/ semiconductor interaction. In contrast, a failure of the integrity of ZrN/ZrB2 metallization at 8000C, when the heat treatment is performed in O2 ambient has been observed.