Abstract
We report on a new approach to quickly synthesize high-quality single crystalline wide band gap silicon carbide (SiC) films for development of high-performance deep ultraviolet (UV) photodetectors. The fabricated SiC based UV photodetectors exhibited high response while maintaining cost-effectiveness and size miniaturization. Focus of the experiments was on studies of electrical and electronic properties, as well as responsivity, response and recovery times, and repeatability of the deep UV photodetectors. Raman scattering spectroscopy and scanning electron microscope (SEM) were used to characterize the SiC materials. Analyses of the SEM data indicated that highly flat SiC thin films have been obtained. Based on the synthesized SiC, deep UV detectors are designed, fabricated, and tested with various UV wavelength lights at different radiation intensities. Temperature effect and bias effect on the photocurrent strength and signal-to-noise ratio, humidity effect on the response time and recovery time of the fabricated detectors have been carefully characterized and discussed. The detectors appear to have a very stable baseline and repeatability. The obtained responsivity is more than 40% higher compared to commercial detectors. The good performance of the photodetectors at operating temperature up to 300 °C remains nearly unchanged.
Highlights
Semiconductor based UV photodetectors can normally be classified into 4 types: photoconductors, metal-semiconductor-metal (MSM) diodes, Schottky barrier and p-i-n photodiodes[1]
Et al reported on high-temperature operation of MSM photodetectors using low-temperature, ion beam-assisted deposition of nanocrystalline Silicon carbide (SiC) thin films and hydrothermal synthesis of ZnO nanorod arrays (NRAs)[15]
Computation simulation indicated that the dark current and photocurrent increased with an increase of temperature
Summary
SiC based photodetectors received: 16 December 2015 accepted: 07 March 2016 Published: 18 March 2016. Based on the synthesized SiC, deep UV detectors are designed, fabricated, and tested with various UV wavelength lights at different radiation intensities. The response strength or the photocurrent of the detector exposed to 300 nm light was almost 7–8 times less than that to 250 nm light at the same radiation intensity, indicating the fabricated SiC based detector is highly sensitive to a short wavelength of UV light. The mechanism responsible for the response-recovery times of the detector is difficult to determine because it depends on many factors such as the nature of samples, light wavelength, doping, doping element and concentration, operating temperature, electrode arrangement, and humidity content, among others. This is because time delay for reaching full intensity for UV lamps after switching on the lamp, and florescence after switching off the lamp would affect the measurement results
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