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通过对 Pt/ Al0 .2 2 Ga0 .78N/ Ga N肖特基二极管的 C- V测量 ,研究分析了 Al0 .2 2 Ga0 .78N/ Ga N异质结界面二维电子气 (2 DEG)浓度及其空间分布 .测量结果表明 ,Al0 .2 2 Ga0 .78N/ Ga N异质结界面 2 DEG浓度峰值对应的深度在界面以下 1.3nm处 ,2 DEG分布峰的半高宽为 2 .3nm ,2 DEG面密度为 6 .5× 10 1 2 cm- 2 .与 Alx Ga1 - x As/ Ga As异质结相比 ,其 2 DEG面密度要高一个数量级 ,而空间分布则要窄一个数量级 .这主要归结于 Alx Ga1 - x N层中～ MV / cm量级的压电极化电场和自发极化电场对 Alx Ga1 - x N/ Ga N异质结能带的调制和 Alx Ga1 - x N/ Ga N异质结界面有更大的导带不连续
Through the C-V measurement of a Pt / Al0.22Ga0.78N / GaN Schottky diode, the two-dimensional electron gas (2 DEG) concentration at the Al0.22Ga0.78N / GaN heterojunction interface was investigated. And its spatial distribution.The measurement results show that the depth corresponding to the peak of the DEG concentration of the Al0.22Ga0.78N / GaN heterojunction interface 2 is 1.3nm below the interface, and the full width at half maximum of the 2 DEG distribution peak is 2.3nm, 2 The density of DEG is 6.5 × 10 12 cm -2. Compared with the Alx Ga 1 - x As / Ga As heterojunction, the density of 2 DEG surface is one order of magnitude higher and the space distribution is one order of magnitude narrower. This is mainly attributed to the modulation of AlxGa1 - xN / GaN heterojunction bandgap and the modulation of AlxGa1 - xN in the AlxGa1 - xN layer by the MV / cm order piezoelectric polarization and spontaneous polarization / Ga N heterojunction interface has a larger conduction band discontinuity