Naveed Afzal

Growth of AlInN film on GaAs substrate and its application to MSM UV photodetector

AlInN film was grown on n-type GaAs (100) substrate by using reactive magnetron co-sputtering technique at 100 °C. The structural analysis revealed polycrystalline nature of the film with its preferred orientation along (002) plane. The band gap of AlInN was estimated to be 3.39 eV from UV–vis reflectance measurements. In order to fabricate AlInN based metal–semiconductor–metal (MSM) photodetector, platinum (Pt) metal contacts were deposited on the film through RF sputtering. The Pt/AlInN/Pt/GaAs MSM photodetector displayed good responsivity under 365 nm UV light. The current–voltage characteristics of the fabricated photodetector showed significant increase in current upon exposure to 365 nm UV light. The current gain for the MSM photodetector under 365 nm UV light at 5 V bias was recorded to be 29.4 whereas the sensitivity of the photodetector was noted to be 2.9 × 103. The response and recovery time were estimated to be 0.70 and 0.72 s respectively. The fabricated device exhibited excellent stability in ON/OFF switching conditions.