Photoresponse of Electrochemically and Spray‐Pyrolytically Deposited CdTe Thin Film Electrodes

Semiconducting thin films of were prepared by both electrochemical and spray‐pyrolytic methods and their photoresponse toward water electrolysis was studied. The photoresponse of electrodeposited films was found to depend on the deposition potential, deposition time, and the annealing time of the film. For the spray‐deposited films prepared at a substrate temperature of 350°C, the photoresponse was dependent on spray time. The conductivity type (n‐ or p‐type) of electrodeposited thin films was found to be dependent on the electrodeposition potential. The and films are formed at negative and positive electrodeposition potentials vs. electrode, respectively. Importantly, it was possible to vary the indirect bandgap of the electrodeposited thin films ( e.g. , 1.55 to 2.0 eV) by controlling the electrodeposition potential or the annealing time. Pyrolytically prepared thin films showed a better photoresponse toward water electrolysis than electrodeposited films.