Room temperature negative differential resistance in AlN/GaN double barrier resonant tunneling diodes grown by RF-plasma assisted molecular beam epitaxy

AlN/GaN double-barrier resonant tunneling diodes (DB-RTD) have been successfully fabricated on (0001) Al/sub 2/O/sub 3/ substrates by molecular beam epitaxy, using RF plasma nitrogen source (RF-MBE). The AlN/GaN DB-RTDs were designed to have 3 monolayers (ML)-thick GaN quantum well and two 4 ML-thick AlN barriers sandwiched by n-GaN contact layers. Clear room temperature negative differential resistance (NDR) with a high peak-to-valley current ratio, as high as 32, was observed.