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We report growth of ZnO nanowires and nanorods using an atmospheric pressure, horizontal MOCVD, without any metal catalyst. The ZnO structures were grown on sapphire (110), Si(111) and SiO 2 /p-Si(111) substrates by controlling the ZnO precursor flow, growth temperature and distance from the injector. Prior to the growth of the nanostructure, a thin film of ZnO was grown at 400°C for 2 mins, DeZ was used as ZnO precursor with a flow rate of 200 sccm, N 2 O was used as oxygen source with a flow rate of 50 sccm and N 2 was used as the carrier gas.

We report the calculated absorption coefficient in Al x Ga 1−x N/GaN quantum well. The calculations account for spontaneous and piezoelectric polarizations and strain induced modifications in band gap and band offsets. The dependence of absorption coefficient and carrier life time on the variations of applied voltage, energy and Al-mole fraction is report in the presence of strain.

The structural, material and field dependence of the THz lasing frequencies are reported for a QCL based upon GaN/AlGaN and GaN/InGaN heterostructures. The inter-subband transition initiated generation of THz followed by the LO-phonon assisted fast depopulation takes into account the appropriate energy band alignments. Valence and conduction band alignments incorporating spin-orbit and crystal field splitting as well as bi-axial strain are used to determine the conduction band offsets as a function of Al or In-mole fraction. We report the bias voltage, quantum well width and mole fraction dependence of lasing frequencies as well as their dependence on Ga or N-face growth. A lower THz frequency is predicted for Ga-face GaN/AlGaN-based QCLs using the revised energy band alignments. Ga-face QCL allows tunabilty of the generated THz radiation by varying the applied bias, whereas, N-face structures are insensitive to the variation of applied bias or current density.