Structural, optical and electrical properties of bare and N monodoped ZnO thin films were investigated. The samples were prepared on glass substrates by spray pyrolysis technique. N doping resulted in p type electrical conductivity as evident from the Hall measurement results. XRD analysis confirmed the structural purity of all the films and compositional analysis by energy dispersive X-ray spectroscopy verified the inclusion of N in doped films in addition to Zn and O. Doping resulted in deterioration in crystallinity. Optical transmittance got diminished with doping due to the degradation in crystallinity as well as due to the presence of deep N related defects as evident from the photoluminescence spectra. Optical energy gap red-shifted with doping percentage due to the introduction of impurity levels near the valence band edge within the forbidden gap with acceptor doping.

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The success of codoping by donor-acceptor impurities in accomplishing p type ZnO thin films deposited by spray pyrolysis technique is reported here. Monodoping ZnO with N altered the conductivity type but the resistivity is too high making it practically impossible to be useful in optoelectronic applications. B-N codoping increased the carrier concentration and obtained comparatively low resistivity because codoping enhanced the acceptor incorporation by forming acceptor-donor-acceptor complex in the band gap. XRD analysis revealed the dependence of dopant incorporation on the texture and microstructure of the films. XPS analysis confirmed the enhancement of N incorporation with codoping. Energy gap value increased for codoped films due to the Burstein-Moss effect, arising from the increase in carrier concentration. Hence the present work envisages the preparation of transparent p type ZnO thin films suitable for tandem thin film solar cells and also for other optoelectronic applications.

The channelling of 3 MeV protons in the ½½¼ direction of silicon has been simulated using Vineyard model taking into account thermally vibrating nuclei and energy loss due to ionelectron interactions. A beam made up of constant energy particles but with spatial divergence has been simulated for the purpose. The values of the minimum scattering yield and half width of the channelling dip are shown to be depth sensitive and agree well with the measured values. The dependence of yield on the angle of incidence has been found to give information of all three types of channelling. The critical angles for the three types of channelling and wavelength of planar oscillations are consistent with the previous calculations.