GaN lateral pn junctions by MBE in situ selective area sublimation and regrowth

We present a technique of patterned in situ molecular beam epitaxy (MBE) selective area sublimation etching of p-type GaN and direct MBE regrowth of n-type GaN to form lateral pn junction structures without air exposure of the junction region. The Mg-doped p-GaN has 2.1×1018/cm3 mobile holes of mobility 4 cm2/V s and the Si-doped n-GaN has 3×1018/cm3 mobile electrons of mobility >100 cm2/V s, both at room temperature. The resulting lateral pn junction exhibits rectification and GaN band-edge electroluminescence at 3.4 eV at forward bias, in addition to blue electroluminescence associated with Mg-doped GaN. We systematically describe the entire MBE etch and regrowth process and expect this vacuum-based technique to enable lateral structures of higher complexity than shown in this initial demonstration.