Deposition of nanocrystalline cuprous oxide films for solar cells application

Cuprous oxide (Cu₂O), a direct band gap semiconductor with energy band gap about 2.0eV, has been regarded as one of the most promising materials for application in photovoltaic cells. Nanocrystalline cuprous oxide thin films has been deposited on glass and Si substrates by dc reactive magnetron sputtering method. The effect of substrate temperature and dc power on the nanocrystalline cuprous oxide thin films microstructure and surface morphology evolution were investigated. The microstructure and surface morphology were determined using X-ray diffractometer and FE-SEM. From FE-SEM analysis, the SEM pictures show that cuprous oxide films exhibit nanosize grains with grain size between 30~60 nm. From X-ray diffraction analysis, a peak of Cu₂O(111l) was observed at the deposition conditions of DC power 100W, deposition pressure 3.3Pa and substrate temperature from 50degC to 200degC. With increasing the substrate temperature from 100degC to 200degC, additional peaks of Cu₂O(110) and Cu₂O(220) were observed. As the DC power was increased to 250W, the X-ray diffraction pattern shows that Cu(111) was observed. Based on the experimental results in this study, nanocyrtsalline Cu₂O films were synthesized at DC power from 100W to 250W and substrate temperature from 50degC to 200degC.