Pulsed laser deposition of Ga doped ZnO films - Influence of deposition temperature and laser pulse frequency on structural, optical and electrical properties

Abstract

The contribution deals with Ga doped ZnO films (deposited from a sintered target composed of 99.0 ZnO and 1.0 wt % of Ga2O3) prepared by pulsed laser deposition (PLD). Experimentally were compared the deposition parameters influence on structural, optical and electrical properties. The variable parameters were: deposition temperature (RT to 500 °C) and growth rate (controlled by laser pulsing repetition frequency in range 2–50 Hz). Investigation by SEM and XRD confirmed columnar structure of prepared films with highly uniform crystallographic orientation regardless of applied deposition parameters. Samples exhibited high optical transparency in VIS region with sharp absorption edge near 380 nm and band gap energies varied between 3.19 and 3.24 eV at room temperature. The best electrical properties (resistivity ∼5.96 × 10−4 Ω cm) was achieved at 400 °C and 10 Hz of laser frequency, however the application of deposition at RT or highest laser frequency (50 Hz) still maintain average resistivity at levels of 10−3 Ω cm. The results suggest that PLD can play an important role in production of high conductive transparent thin film deposited on temperature sensitive organic materials at RT deposition levels.