Band offsets of polar and nonpolar GaN/ZnO heterostructures determined by synchrotron radiation photoemission spectroscopy
Band offsets of polar and nonpolar GaN/ZnO heterostructures determined by synchrotron radiation photoemission spectroscopy
复制标题
DOI：
10.1002/pssb.201046459
复制
发表时间：
2011-04
期刊：
影响因子：
--
通讯作者：
J. Liu;A. Kobayashi;S. Toyoda;H. Kamada;A. Kikuchi;J. Ohta;H. Fujioka;H. Kumigashira;M. Oshima
中科院分区：
文献类型：
--
作者：
J. Liu;A. Kobayashi;S. Toyoda;H. Kamada;A. Kikuchi;J. Ohta;H. Fujioka;H. Kumigashira;M. Oshima
在室温下通过脉冲激光沉积制备了C面（极性）和m面（非极性）GaN/ZnO异质结构，并通过同步辐射光电子能谱表征了它们的电子结构。根据核心能级的结合能和价带最大值，发现极性和非极性 GaN/ZnO 异质结的价带偏移分别为 0.7 ± 0.1 和 0.9 ± 0.1 eV。两种异质结构均显示 II 型能带结构，导带偏移分别为 0.8 ± 0.1 和 1.0 ± 0.1 eV。 GaN 和 ZnO 在非极性 GaN/ZnO 异质结中表现出朝向界面的向上和向下的能带弯曲。然而，GaN 和 ZnO 在极性异质结中都表现出向上的能带弯曲，这归因于负电荷。 N 1s 光谱分析表明，N-O 键仅存在于极性界面，这可能导致负电荷的形成。
C‐plane (polar) and m‐plane (nonpolar) GaN/ZnO heterostructures have been fabricated by pulsed laser deposition at room temperature, and their electronic structures have been characterized by synchrotron radiation photoemission spectroscopy. Based on the binding energies of core levels and valence band maximum values, the valence band offsets have been found to be 0.7 ± 0.1 and 0.9 ± 0.1 eV for polar and nonpolar GaN/ZnO heterojunctions, respectively. Both heterostructures show type‐II band configurations with conduction band offsets of 0.8 ± 0.1 and 1.0 ± 0.1 eV, respectively. GaN and ZnO show upward and downward band bending toward the interface in the nonpolar GaN/ZnO heterojunction. However, both GaN and ZnO show upward band bending toward the interface in the polar heterojunction, which is attributed to negative charges. Analysis of N 1s spectra has revealed that N–O bonds exist only at the polar interface, which probably caused the formation of the negative charges.