MgO界面层对n-ZnO纳米棒/p-GaN异质结LED光电性能的影响

为了较好地实现n-ZnO的电致发光(EL),利用水热法在p-GaN外延片上制备了ZnO纳米棒阵列,构造了n-ZnO纳米棒/p-GaN异质结LED原型器件,并研究了MgO界面层对器件光电性能的影响。结果表明,n-ZnO纳米棒/p-GaN异质结器件具有明显的二极管整流效应。室温、正向偏压下,n-ZnO纳米棒/p-GaN异质结LED仅在430nm附近具有单一的发光峰,而n-ZnO纳米棒/MgO/p-GaN异质结LED的电致发光光谱由一个从近紫外到蓝绿光区的宽发光带组成。结合光致发光(PL)谱和Anderson能带模型,深入分析了n-ZnO纳米棒/p-GaN异质结的载流子复合机制。

Effect of MgO interface layer on photoelectric properties of n-ZnO nanorods/p-GaN heterojunction LED

Limited by the technology conditions,carrier concentration and Hall m obility of p-GaN are lower than those of n-ZnO.When the n-ZnO nanorods/p-GaN heterojunction device works under forward bias,the electroluminescence (EL) mainly origins from p-GaN side.In order to realize electroluminescence of n-Zn O,in this paper,heterojunction LEDs based on arrays of ZnO nanorods were fabricated on p-GaN films by hydrothe rmal method,and the effects of MgO interface layer on the photoelectric properties of the device are studied. The results show that all the devices demonstrate nonlinear rectifying behaviour.At room temperature,the EL sp ectra of the n-ZnO nanorods/p-GaN heterojunction diodes display one emission peak cente red at about 430nm under forward bias.However,the EL spectra of n-ZnO nanorods/MgO/p-GaN heterostruct ure LED exhibit a broad emission band from near ultraviolet to blue-green region.Combining the photolu minescence (PL) spectrum and Anderson energy band diagram,the mechanisms of radi ative recombination in n-ZnO nanorods /p-GaN heterojunction LEDs are discussed in detail.