Metalorganic vapour phase epitaxy of GaAs/AlGaAs nanoheterostructures for a quantum cascade laser

Short-period GaAs/AlGaAs superlattices, an active region, and a quantum cascade laser heterostructure have been grown by metalorganic vapor phase epitaxy, and their characteristics have been studied by high-resolution X-ray diffraction, transmission electron microscopy, and photoluminescence spectroscopy. The heterostructures have been used to produce quantum cascade lasers emitting near 10 μm. Their output pulse power at 77 K is above 200 mW.     

Phase Formation during the Surface-Diffusion Growth of Ti–Co–Si–N and Ti–Co–N Thin Films on Si and SiO2

The kinetics of phase formation in Ti–Co–Si–N and Ti–Co–N thin films on Si and SiO₂is investigated experimentally. With the deposition on Si, rapid thermal annealing (T 900°C) is shown to cause phase separation that ends in a TiN/CoSi₂/Si structure. If SiO₂is used, the alloy reacts with the substrate to produce compounds that are difficult to remove with selective etchants. This limits the potential uses of this process in the fabrication of contact systems for CMOS devices. It is shown that structure- and phase-dissimilar films can be formed on Si and SiO₂by means of the surface-diffusion reactions between a Ti–Co–Si–N or Ti–Co–N alloy and the substrate at 650–700°C. The effect of a TiN, Ti, or CoSi₂thin layer at the alloy–substrate interface on the phase separation is investigated.     

On the control efficiency of a high-power laser thyristor emitting in the 890–910 nm spectral range

A high power laser-thyristor structure providing low current-related and optical losses is developed. The possibility of controlling the lasing turn-on delay time of the laser thyristor in the 8–2600 ns range is demonstrated. The minimum values of the energy and amplitude of the control current-density pulse, required for turning-on the laser thyristor with a peak output power of 28 W, are 1.4 nJ and 0.6 A/cm², respectively.