Modulation of intrinsic defects in vertically grown ZnO nanorods by ion implantation.

Intrinsic defects created by chemically inert gas (Xe) ion implantation in vertically grown ZnO nanorods are studied by optical and X-ray absorption spectroscopy (XAS). The surface defects produced due to dynamic sputtering by ion beams control the fraction of O and Zn with ion fluence, which helps in tuning the optoelectronic properties. The forbidden Raman modes related to Zn interstitials and oxygen vacancies are observed because of the weak Fröhlich interaction, which arises due to disruption of the long-range lattice order.

Temperature-dependent excitonic emission characteristics of lead-free inorganic double perovskites and their third-order optical nonlinearities.

We report temperature-dependent photoluminescence (PL) in the temperature range between 77 K and 300 K, and room temperature nonlinear optical (NLO) properties of solution processed lead-free CsNaBiI (CNBI) and CsKBiI (CKBI) perovskite films. The de-convolution analysis of temperature-dependent PL spectra showed thermal quenching behavior of free-exciton (FX) emission, an unusual blue-shift of PL emission, and line broadening with increasing temperature as a consequence of strong exciton-phonon interaction. The nonlinear refractive index () and nonlinear absorption coefficient () of both the CNBI and CKBI films are determined using a closed aperture (CA) and open aperture (OA) Z-scan technique, respectively.

Excitonic properties of layer-by-layer CVD grown ZnO hexagonal microdisks.

We have investigated the excitonic properties of highly crystalline ZnO hexagonal microdisks grown by the chemical vapour deposition technique. It was observed that a suitable negative catalyst like chlorine suppresses the crystal growth along the (0001) direction. We propose a qualitative model for the experimentally observed layer-by-layer growth mechanism of the microdisks.