We report on the solar-blind metal-semiconductor-metal (MSM) UV photodetector fabricated on the Al0.3Ga0.7N/GaN heterostructure layer grown on sapphire(0 0 0 1) by metalorganic chemical vapor deposition. The use of high-temperature (HT)-AIN interlayer in Al0.3Ga0.7N/GaN epilayer and its effects on the grown structures were explored. The Al0.3Ga0.7N-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 12.5 ns without reverse bias and very low dark current due to low noise with a typical value of 72 pA and 0.15 muA 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. (C) 2003 Elsevier Science B.V. All rights reserved.