Magnetotransport in Gd-implanted wurtzite GaN∕AlxGa1−xN high electron mobility transistor structures

Ga N ∕ Al x Ga 1 − x N heterostructures containing a two-dimensional electron gas (2DEG) 27nm underneath the surface were focused-ion-beam implanted with 300keV Gd ions at room temperature. At 4.2K, current-voltage characteristics across implanted rectangles showed that the structures remained conducting up to a Gd dose of 1×1012cm−2. Extraordinary Hall effect and anisotropic magnetoresistance were observed at T=4.2K for structures implanted with 3×1011cm−2 Gd. This dose corresponds to a 23% reduction in electron concentration and a decrease in the mobility by a factor of 14 at 4.2K. However, the still-conducting 2DEG is now embedded in a ferromagnetic semiconductor which opens the possibility to polarize its spins.