Metal–Semiconductor–Metal Ultraviolet Photodetectors Based on Al Nanoparticles in 4H-SiC Microholes

A significant ultraviolet (UV) detection enhancement is realized by etching microhole (MH) arrays and localized surface plasmon resonance (LSPR) of Al nanoparticles (NPs) on 4H-SiC metal–semiconductor–metal (MSM) photodetectors (PDs). 4H-SiC PDs with different diameters of MHs are fabricated, which exhibit an ultralow dark current of approximately 5.0 × 10 –15 A at 5 V bias. The PD with 3 μm MH exhibits the best performance, and its peak responsivity is 35% higher than that of device without MH. The peak responsivity of PDs with both 3 μm MH and NPs enhanced nearly 6 times that without Al NPs. The PD with both 3 μm MH and Al NPs indicates the best detection performance, with a maximum detectivity of 4.0 × 10 13 Jones at 270 nm, which is nearly an order of magnitude higher than devices without Al NPs. The fabricated MH and Al NPs MSM PDs have a high response on the order of nanoseconds, with a rise/decay time of 2.1 ns/2.5 ns at 5 V bias. The complementary optical properties of MH and Al NPs with 4H-SiC can promote the development and application of high-performance UV PDs.