Photoconductivity studies of hybrid ZnTe/MgPc thin films prepared by physical vapour deposition

摘要

The novel hybrid ZnTe/MgPc thin films of thickness 300 nm – 400 nm were prepared by vacuum deposition technique at 10-5 Torr. The as deposited films on glass substrates at the room temperature were annealed upto150ºC in order to ensure crystalline phase of the hybrid. The optical studies indicate enhancement of optical absorption of magnesium phthalocyanine by consistently increasing zinc telluride in ascending proportion. Consequently broadening of absorption range from visible to near IR region was found which resulted in increased photoconductivity for the compound. The activation energy proportionally decreased from 2.25 eV to 1.9 eV. The SEM images of the films show very smooth surface morphology devoid of pinholes and grain boundaries complimenting photoconductivity enhancement. EDAX results confirm the presence of magnesium in the hybrid thin film. The band gap is reduced from 2.6eV to 1.5eV. Annealing upto an optimum temperature results in enhancement of photoconductivity