Analysis of temperature-dependent characteristics of a 4H-SiC metal-semiconductor-metal ultraviolet photodetector

Abstract

We investigate the temperature dependence of current-voltage and spectral response characteristics of a 4H-SiC metal-semiconductor-metal (MSM) ultraviolet photodetector in the temperature range from room temperature to 800 K with two-dimensional (2D) numerical simulator ISE-DESSIS. It is found that the dark current and photocurrent increase with the increasing temperature. For the range of 500–800 K, the dark current increases by nearly a factor 3.5 every 150 K larger than that of photocurrent, leading to a negative effect on photodetector current ratio (PDCR). Nevertheless, the PDCR is still greater than 200 even at 800 K, which exhibits the excellent thermal stability. In addition, the responsivity has an unsymmetrical trend. As temperature rises, it is clear that a remarkable red-shift of 12 nm occurs and overall responsivity is enhanced for longer wavelength. While the short-wave-length response remains relatively independent of temperature. The mechanism of indirect and direct band absorption transition is responsible for temperature-dependent spectrum distribution. These findings provide a significant insight on the design of the MSM detector operated at elevated temperature.