Room temperature negative differential resistance characteristics of polar Ⅲ-nitride resonant tunneling diodes

摘要

Ⅲ-nitride resonant tunneling diodes (RTDs), consisting Al_(0.2)Ga_(0.8)N/GaN double-barrier (DB) active layers, were grown on c-plane lateral epitaxial overgrowth (LEO) GaN/sapphire and c-plane freestanding (FS) GaN. RTDs on both templates, fabricated into mesa diameters ranging from 5 to 35 μm, showed negative differential resistance (NDR) at room temperature. NDR characteristics (voltage and current density at NDR onset and current-peak-to-valley ratio) were analyzed and reported as a function of device size and substrate choice. Our results show that LEO RTDs perform as well as FS ones and DB active layer design and quality have been the bottlenecks in Ⅲ-nitride RTDs.