Basic requirements of spin-flip Raman scattering on excitonic resonances and its modulation through additional high-energy illumination in semiconductor heterostructures

We describe the major requirements to experimentally perform and observe resonant spin-flip Raman scattering on excitonic resonances in low-dimensional semiconductors. We characterize in detail the properties of this resonant light scattering technique and evaluate the criteria, which must be fulfilled by the experimental setup and the semiconductor sample studied to be able to observe a spin-flip scattering process. We also demonstrate the influence of additional unpolarized laser illumination with energies, which exceed considerably the band gap energy of the semiconductor nanostructure under study, on the resonantly excited electron spin-flip scattering in InAs-based quantum dot ensembles as well as on the paramagnetic Mn-ion spin-flip in (Zn,Mn)Se/(Zn,Be)Se quantum wells.

Ultra Fast High Temperature Microwave Annealing of Ion Implanted Large Bandgap Semiconductors

In this work, the surface, lattice and electrical properties of implanted 4H-SiC, GaN and ZnO, annealed by a novel ultra-fast microwave heating method, are compared to that of conventional annealing methods. In this new method, amplified and variable frequency microwaves from a signal generator are directly coupled to the semiconductor sample through a microwave head. Since, the microwaves are only absorbed by the sample, without heating of the ambient, ultra-high heating (> 2000°C/s) and cooling rates and very high (2100°C) annealing temperatures can be reached. For Al and P species implants into 4H-SiC, record low resistivity values were achieved with a lattice quality better than that of the virgin crystal. This annealing method improved the lattice quality of un-implanted region below the surface implanted region as well. Improved material characteristics were also obtained for GaN and ZnO.

ANALYSIS OF REDISTRIBUTION OF RADIATION DEFECTS TAKING INTO ACCOUNT DIFFUSION AND SEVERAL SECONDARY PROCESSES

In this paper, we analyzed the evolution of concentration of radiative defects, which is generated in a semiconductor sample during ion implantation. Approximate analytical approach for the description of the evolution of concentration of radiative defects with account diffusion and some secondary processes (recombination of the point defects and generation of divacancies) has been used. Discontinuity of the ions in space and time has been also accounted. The main results are: (i) the estimation of dependencies of the defect concentration from depth at different values of dose (irradiation time), (ii) the different amorphization doses from the density of current of the ions for the more common case in comparison with those considered in literature. As an example, we consider the implantation of ions of neon into a sample of the silicon.

DYNAMICS OF RADIATIVE POINT DEFECTS IN GALLIUM ARSENIDE DURING RELAXATION OF LOCAL HEATING

In this paper we have analyzed the dynamics of redistribution of the radiative point defects in gallium arsenide during relaxation of the local heating in a semiconductor sample, generated by a radiative particle in the initial stage of stabilization of clusters of defects. We calculated: (i) the maximum heating temperature of a semiconductor sample, and (ii) the point defect diffusion coefficient corresponding to the maximum temperature.