Characterization of UV photodetector based on ZnO/diamond film.

In this study, a ZnO/diamond structure ultraviolet (UV) photodetector was fabricated and investigated. ZnO films with thickness of 50 and 100 nm were deposited on half of diamond substrates by sputtering technique. Then, electrodes were patterned on ZnO and diamond areas to form photodetectors. The photocurrent gain in the UV region has been strongly influenced by ZnO film. ZnO films with thickness of 50 and 100 nm on diamond substrates reaches 14.3 and 308 A/W, respectively. Both of peak responsivities were located at 270 nm. Additionally, two shoulder peaks around 240 nm and 290 nm were observed for ZnO/diamond photodetector, which may stem from diamond and ZnO, respectively.

Reducing Threading Dislocations of Single-Crystal Diamond via In Situ Tungsten Incorporation.

A lower dislocation density substrate is essential for realizing high performance in single-crystal diamond electronic devices. The in-situ tungsten-incorporated homoepitaxial diamond by introducing tungsten hexacarbonyl has been proposed. A 3 × 3 × 0.5 mm3 high-pressure, high-temperature (001) diamond substrate was cut into four pieces with controlled experiments. The deposition of tungsten-incorporated diamond changed the atomic arrangement of the original diamond defects so that the propagation of internal dislocations could be inhibited. The SEM images showed that the etching pits density was significantly decreased from 2.8 × 105 cm-2 to 2.5 × 103 cm-2. The reduction of XRD and Raman spectroscopy FWHM proved that the double-layer tungsten-incorporated diamond has a significant effect on improving the crystal quality of diamond bulk. These results show the evident impact of in situ tungsten-incorporated growth on improving crystal quality and inhibiting the dislocations propagation of homoepitaxial diamond, which is of importance for high-quality diamond growth.