Photovoltaic effect observed in transparent p-n heterojunctions based on oxide semiconductors

Transparent p-n junctions composed of zinc oxide, copper-aluminum oxide and indium-tin oxide films were fabricated by pulsed laser deposition on glass substrates at temperatures as low as 400 degreesC. Diode characteristics in the current-voltage response and the photovoltaic effect were observed for the junctions fabricated. The photovoltaic junction had an optical transparency of more than 43% for the wavelengths lambda > 500 nm, and exhibited photovoltage as large as 80 mV when it was illuminated by a LED of lambda approximate to 470 nm. The properties of the photovoltaic transparent junction seemed to be degraded by the inadequate crystallinity of the copper-aluminum oxide layer. The ZnO/Cu-Al-O/ITO/glass structure developed in this study has demonstrated a possible application of transparent solar cells. (C) 2003 Elsevier B.V. All rights reserved.