Polarization engineered deep ultraviolet nanowire LEDs integrated on silicon and metal substrates

AlGaN nanowire heterostractures are promising for realization of efficient ultraviolet LEDs due to their tolerance to strain [1] and their ability to be grown and electronically integrated on silicon wafers. Previously we developed polarization-induced nanowire LEDs that include Al composition grading resulting in n-type and p-type doping within nanowires [2]. Because the barriers in this structure are A1N, we can incorporate AlGaN quantum disk active regions with emission tunable out to deep ultraviolet wavelengths. These nanowire heterostractures exhibit dominant N-face polarity [3] which has the advantage of allowing for n-type top contacts favorable for Nitride LEDs. However, this poses a challenge due to the difficultly of forming a bottom p-type contact to p-AlGaN.