NH_3-MBE生长极化场二维电子气材料

Polarization induced two-dimensional electron gases in GaN/AlN/GaN heterostructures grown by ammonia-molecular beam epitaxy

介绍了用NH3 MBE技术在蓝宝石C面上外延的高质量的GaN单层膜以及GaN AlN GaN极化感应二维电子气材料。外延膜都是N面材料。形成的二维电子气是“倒置二维电子气”。GaN单层膜的室温电子迁移率为 30 0cm2 Vs。二维电子气材料的迁移率为 6 80cm2 Vs(RT)和 1 70 0cm2 Vs(77K) ,相应的二维电子气的面密度为 3.2× 1 0 13cm- 2 (RT)和 2 .6x1 0 13cm- 2 (77K ) .

High quality GaN film and GaN/AlN/GaN heterostructures have been grown on (0001) sapphire by ammonia-molecular beam epitaxy. The epitaxial layers are all N surface materials. The two dimensional electron gases (2DEG) are formed in the GaN/AlN/GaN heterostructures and considered as ' inverted '. Hall electron mobility in a GaN epitaxial layer with thickness of 1.2 μm is 300cm 2/Vs at room temperature. Hall electron mobilities in the GaN/AlN/GaN 2DEG heterostructure are 680 cm 2/Vs at room temperature and 1750 cm 2/Vs at 77K. Due to the lattice-mismatch between the GaN and AlN layers and the AlN layers being too thick, cracks are formed in the GaN/AlN/GaN hetrostructures.