P-AgCoO2/n-ZnO heterojunction diode grown by rf magnetron sputtering

Abstract

P-type transparent semiconducting AgCoO2 thin films were deposited by rf magnetron sputtering of sintered AgCoO2 target. The AgCoO2 films grown by rf sputtering were highly c-axis oriented showing only (001) reflections in the X-ray diffraction pattern unlike in the case of amorphous films grown by pulsed laser deposition (PLD). The bulk powder of AgCoO2 was synthesized by hydrothermal process. The optical bandgap was estimated as 4-15 eV and has a transmission of about 50% in the visible region. The temperature dependence of conductivity shows a semiconducting behaviour. The positive sign of Seebeck coefficient (+220 μVK-1) indicates p-type conductivity. Transparent p-n heterojunction on glass substrate was fabricated by rf magnetron sputtering of p-AgCoO2 and n-type ZnO : Al thin films. The structure of the diode was glass/ITO/n-ZnO/p-AgCoO2. The junction between p-AgCoO 2 and n-ZnO was found to be rectifying. © Indian Academy of Sciences.