Department of Electronic Science and Technology and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, People's Republic of China.
ACS Appl Mater Interfaces. 2012 May;4(5):2521-4. doi: 10.1021/am300223y. Epub 2012 May 11.
High-quality Mn:ZnO (MZO) film had been prepared on N-GaN coated sapphire substrates followed by postdeposition thermal annealing treatment at 700 °C. For the annealed MZO/GaN heterojunction, a 15 nm cubic structural ZnGa(2)O(4) layer was observed at the MZO/GaN interface through transmission electron microscope analysis. Through electroluminescence (EL) measurement, the formation of the nanointerface results in an EL transition from ultraviolet- to red-dominant mode for n-Mn:ZnO/N-GaN heterojunction light-emitting diodes (LEDs). The heterojunction LED showed a rectification ratio of ∼2.0 × 10(5) at ±2 V, a dark current of 3.5 nA at -2 V and a quite strong red EL with a low turn-on voltage of 3 V. On the basis of the energy band diagram, we think the EL transition from ultraviolet- to red-dominant mode is mainly due to the formation of a thin oxide blocking nanolayer at the MZO/GaN interface during the annealing process.
已在 N-GaN 覆盖的蓝宝石衬底上制备出高质量的 Mn:ZnO（MZO）薄膜，随后在 700°C 下进行后沉积热退火处理。对于退火后的 MZO/GaN 异质结，通过透射电子显微镜分析在 MZO/GaN 界面观察到 15nm 立方结构的 ZnGa(2)O(4)层。通过电致发光（EL）测量，纳米界面的形成导致 n-Mn:ZnO/N-GaN 异质结发光二极管（LED）的 EL 跃迁从紫外主导模式变为红主导模式。该异质结 LED 在 ±2V 时的整流比约为 2.0×10(5)，在-2V 时的暗电流为 3.5nA，并且具有很强的红色 EL，开启电压低至 3V。基于能带图，我们认为 EL 从紫外主导模式到红主导模式的转变主要是由于在退火过程中在 MZO/GaN 界面形成了一个薄的氧化物阻挡纳米层。
