Characteristics of UV photodetector fabricated by Al_0.3Ga_0.7N/GaN heterostructure

We report on the solar-blind metal-semiconductor-metal (MSM) UV photodetector fabricated on the Al_0.3Ga_0.7N/GaN heterostructure layer grown on sapphire(0001) by metalorganic chemical vapor deposition. The use of high-temperature (HT)-AlN interlayer in Al_0.3Ga_0.7N/GaN epilayer and its effects on the grown structures were explored. The Al_0.3Ga_0.7N-based interdigitated MSM photodetector has been successfully fabricated and characterized. The device reveals that a visible rejection is more than 3 orders of magnitude with a cutoff wavelength at 292 nm and the responsivity is up to 0.15 A/W. Also, MSM UV photodetector shows very fast response time of 12.5ns without reverse bias and very low dark current due to low noise with a typical value of 72 pA and 0.15 μA at 10 and 40 V, respectively. The obtained results are very promising for the enhancement of solar-blind MSM UV photodetectors and simultaneously very sufficient for application in UV region such as UV astronomy, UV missile detection and visible blindness materials.