Eelctrodeposition of Nanocrystalline Cuprous Oxide Thin Films

Abstract

Cuprous oxide is an attractive material for solar energy applications because it is low cost, non toxic and has a direct band gap of 2 eV. Electrodeposition for preparing cuprous oxide thin films is important because it provides the possibility of depositing n-type Cu2O thin films on conducting substrates, compared with p-type Cu2O films resulted in many other techniques. Electrodeposition of cuprous oxide is possible in a near neutral aqueous bath containing cupric ions and in a potential domain about 0 to 300 mV vs. SCE. Structural and morphological studies reveal that single phase polycrystalline films of crystalline size 1-2 ?m to 100nm of Cu2O can be electrodeposited by controlling the deposition parameters. It is revealed that for nanostructured film deposition low temperature deposition in galavanostatic mode is more suitable. Photoresponses of the films are very sensitive to the nature of the substrates. Particularly, n-type or p-type behavior of photoresponse is determined by the relative magnitudes of the photosignals produced by the photo electrodes. This is revealed by the spectral responses of the short and the long wavelengths of the illuminated light. The general photoresponse behavior is the same whether the electrode is in contact with an electrolyte or with a metal. This study reveals the possibility of electrodepositing nanocrystalline cuprous oxide thin films on conducting substrates. These films will be very useful in applications of solar energy converting devices.