调制掺杂Al<sub>x</sub>Ga<sub>1-x</sub>NGaN异质结磁输运研究

调制掺杂Al_xGa_1-xNGaN异质结磁输运研究

摘要: 通过低温和高磁场下的磁输运测量, 首次在Al_0.22Ga_0.78N/GaN异质结中观察到了舒勃尼科夫德哈斯振荡的双周期特性, 发现在Al_0.22Ga_0.78N/GaN异质结的三角势阱中产生了二维电子气 (2DEG)的第二子带占据, 发生第二子带占据的阈值 2DEG浓度估算为7.2×10¹² cm^-2, 在阈值 2DEG浓度下第一子带和第二子带能级的距离计算为75 meV。

Abstract: Magnetoresistance of modulation doped Al_0.22Ga_0.78 N/GaN heterostructures has been studied by means of magnetotransport measurements at low temperatures and high magnetic fields. The double periodicity of the Shubnikov de Hass oscillations was observed. It was found that the occupation of the first two subbands by the two dimensional electron gas（2DEG） in the triangular quantum well at the Al_0.22Ga_0.78 N/GaN heterointerface took place when the 2DEG sheet concentration reached 7.2×10¹² cm^-2 . The energy separation of the first and the second subbands in the quantum well was determined to be 75 meV just before the second subband was occupied.