Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seoul 120-749, Republic of Korea.
Nanoscale. 2014 Apr 7;6(7):3611-7. doi: 10.1039/c3nr05328h.
A novel heterojunction white light emitting diode (LED) structure based on an array of vertically aligned surface-passivated p-type porous Si nanowires (PSiNWs) with n-type amorphous In-Ga-Zn-O (a-IGZO) capping is introduced. PSiNWs were initially synthesized by electroless etching of p-type Si (100) wafers assisted by Ag nanoparticle catalysts and then surface-passivated by thermal oxidation. The nanowires synthesized by metal-assisted electroless etching were found to have longitudinally varying nanoporous morphologies due to differences in the duration of exposure to etching environment. These PSiNWs were optically active with orange red photoluminescence consisting of dark red to yellow emissions attributable to quantum confinement effects and to modified band structures. The LED structures emitted visible white light while exhibiting rectifying current-voltage characteristics. The white light emission was found to be the result of the combination of dark red to yellow emissions originating from the quantum confinement effect within the PSiNWs and green to blue emissions due to the oxygen-deficiency-related recombination centers introduced during the surface oxidation.
一种基于垂直排列的表面钝化 p 型多孔硅纳米线（PSiNWs）与 n 型非晶态 In-Ga-Zn-O（a-IGZO）覆盖层的新型异质结白光发光二极管（LED）结构被引入。PSiNWs 最初通过 Ag 纳米颗粒催化剂辅助的电化学腐蚀法在 p 型 Si（100）晶片上合成，然后通过热氧化进行表面钝化。通过金属辅助电化学腐蚀合成的纳米线由于暴露于腐蚀环境的时间不同，具有纵向变化的纳米多孔形态。这些 PSiNWs 具有橙红色光致发光，由归因于量子限制效应和改性能带结构的深红色到黄色发射组成，具有光学活性。LED 结构在表现出整流电流-电压特性的同时发射可见光白光。发现白光发射是 PSiNWs 内量子限制效应产生的深红色到黄色发射以及表面氧化过程中引入的氧缺陷相关复合中心产生的绿色到蓝色发射的组合结果。
