Double Schottky metal–semiconductor–metal based GaN photodetectors with improved response using laser MBE technique

Present work demonstrates the fabrication of Gallium nitride (GaN) based ultraviolet metal–semiconductor–metal (MSM) photodetectors on Si(111) substrate using the Laser MBE technique. MSM photodetectors based on Au, Pd and ITO contacts were fabricated to study the effect of electrodes on the observed UV photoresponse. Temporal response of the fabricated photo-detectors at a regular interval of 20 s ON–OFF cycle revealed that ITO is the best-suited electrode material for the fabrication of photo-detectors with high detectivity, sensitivity and low dark current. The ITO/GaN/ITO double Schottky photodetector showed the maximum responsivity of 0.27 A/W at an applied bias of 1 V towards 325 nm wavelength radiation. The value of detectivity, dark current and the ratio of normalized photocurrent to dark current for ITO/GaN/ITO was found to be 1.73 × 1013 Jones, 0.24 pA and 0.8 × 104, which is significantly enhanced as compared to the corresponding values reported by other research groups for MSM photodetectors.