Pulsed laser deposition of p-type α-AgGaO2 thin films

Polycrystalline α-AgGaO2 powders were prepared by the hydrothermal conversion of β-AgGaO2. The β-AgGaO2 was synthesized by the ion exchange reaction between NaGaO2 and molten AgNO3 under nitrogen atmosphere. The α-AgGaO2 thus synthesized was used as the target for pulsed laser ablation. The films grown on α-Al2O3 (0001) single crystal substrates are crystalline and are 50% transparent in the visible region. The temperature dependence of conductivity shows a semiconducting behaviour with room temperature conductivity 3 × 10− 4 Scm− 1. The positive sign of Seebeck coefficient (+ 70 μVK− 1) demonstrated the p-type conduction in the films. Transparent p–n heterojunctions on a glass substrate were fabricated. The structure of the device was glass/ITO/n-ZnO/p-AgGaO2. The ratio of forward to reverse current was more than 100 in the range of − 1.5 V to + 1.5 V.