Photo-induced current and its degradation in Al4C3/Al2O3 (0001) grown by metalorganic chemical vapor deposition

Al4C3 layers have been grown on Al2O3 (0001) by metalorganic chemical vapor deposition. Trimethylaluminum and methane were used as source materials for aluminum and carbon, respectively. Depending on the growth conditions, the growth rate was significantly changed. The most suitable growth temperature was 1150 °C. Fresh samples had a yellowish color. Peaks at 32 and 35° observed by 2θ-ω mode X-ray diffraction scans confirmed the presence of hexagonal Al4C3. Experiments detected photo-induced current (PIC). PIC measured at 30 V dc was observed at Al4C3/Al2O3 (0001) at the 10 nA scale. PIC in Al4C3 increased with a decrease in the irradiated wavelength. This phenomenon was also observed in absorption coefficient experiments. It was also verified that the electrical conductivity of Al4C3 significantly deteriorated due to oxidation. PIC was also continuously reduced during Al4C3 oxidation. After a certain period of time, it was observed that the Al4C3 layer separated from the Al2O3 (0001) substrate. These results suggest that PIC can be useful in photodetectors that can be used in vacuum or in other gases that do not contain oxygen.