Graduate School of Information Science and Technology and Research Center for Integrated Quantum Electronics, Hokkaido University, North 14 West 9, Sapporo 060-0814, Japan.
Nanotechnology. 2019 Mar 29;30(13):134002. doi: 10.1088/1361-6528/aafce5. Epub 2019 Jan 9.
We report a systematic study on the current injection and radiative carrier recombination in InP nanowire (NW) light-emitting diodes (LEDs). The InP NWs with axial p-n structures, grown by selective-area metal organic vapor-phase epitaxy, had mixed crystal structures between those of zincblende and wurtzite, mainly in the p-regions. The temperature dependence of the current-voltage (I-V), electroluminescence (EL), and current-light output (I-L) characteristics was investigated. The temperature dependence of the I-V characteristics revealed that tunneling was the main mechanism of carrier transport through the p-n junction in the present NW-LEDs. The temperature and bias voltage dependences of EL showed a complex but systematic behavior, where peaks exhibiting bias-dependent and independent energy positions coexisted and the relative intensity showed a transition with increasing temperature. The external quantum efficiency showed a droop at low temperatures, indicating a reduced injection efficiency at low temperatures. These observations were explained by the radiative and nonradiative tunneling, and suggested a strong effect of the nonradiative tunneling at low temperatures.
我们对 InP 纳米线（NW）发光二极管（LED）中的电流注入和辐射载流子复合进行了系统研究。通过选择性区域金属有机气相外延生长的轴向 p-n 结构 InP NW 具有闪锌矿和纤锌矿之间的混合晶体结构，主要在 p 区。我们研究了电流-电压（I-V）、电致发光（EL）和电流-光输出（I-L）特性随温度的变化。I-V 特性的温度依赖性表明，在本 NW-LED 中，隧道效应是载流子通过 p-n 结传输的主要机制。EL 的温度和偏置电压依赖性表现出复杂但系统的行为，其中具有偏置相关和独立能量位置的峰共存，并且相对强度随温度升高而发生转变。外量子效率在低温下出现下倾，表明低温下的注入效率降低。这些观察结果通过辐射和非辐射隧道效应得到了解释，并表明在低温下非辐射隧道效应对其有强烈影响。
