The study on the optical properties of GaN detector on the 6H-SiC substrates

We have studied the optical properties of the ultraviolet detector based on the GaN epilayer grown on 6H-SiC substrate by metalorganic chemical vapor deposition. We obtained the detectable energy span of the device up to ultraviolet by photocurrent measurement. The spectral responsivity remained nearly constant for wavelengths from 250 to 365 nm and dropped by three orders of magnitude within 10 nm of the band edge (by 380 nm). The detector was measured to have a responsivity of 133 A/W at a wavelength of 360 nm under a 5-V bias, and the voltage-dependent responsivity was performed. Furthermore, an easy method was developed to determine the response time and the relationship between response time and bias was obtained.