Transparent diode heterojunction on ITO coated glass substrates was fabricated using p-type AgCoO2 and n-type ZnO films by pulsed laser deposition (PLD). The PLD of AgCoO2 thin films was carried out using the pelletized sintered target of AgCoO2 powder, which was synthesized in-house by the hydrothermal process. The band gap of these thin films was found to be similar to 3.89 eV and they had transmission of similar to 55% in the visible spectral region. Although Hall measurements could only indicate mixed carrier type conduction but thermoelectric power measurements of Seebeck coefficient confirmed the p-type conductivity of the grown AgCoO2, films. The PLD grown ZnO films showed a band gap of similar to 3.28 eV, an average optical transmission of similar to 85% and n-type carrier density of similar to 4.6 x 1019 cm(-3). The junction between p-AgCoO2 and n-ZnO was found to be rectifying. The ratio of forward current to the reverse current was about 7 at 1.5 V The diode ideality factor was much greater than 2. (c) 2007 Elsevier B.V. All rights reserved.