多孔硅光致发光峰半峰全宽的压缩

Compress Full Width at Half Maximum of Porous Silicon Photoluminescence Spectrum

硅发光对于在单一硅片上实现光电集成是至关重要的。目前已有的使硅产生发光的方法有:掺杂深能级杂质、掺稀土离子、多孔硅、纳米硅以及S i/S iO2超晶格。声空化所引发的特殊的物理、化学环境为制备光致发光多孔硅薄膜提供了一条重要的途径。实验表明,声化学处理对于改善多孔硅的微结构,提高发光效率和发光稳定性都是一项非常有效的技术。超声波加强阳极电化学腐蚀制备发光多孔硅薄膜,比目前通用的常规方法制备的样品显示出更优良的性质。这种超声波的化学效应源于声空化,即腐蚀液中气泡的形成、生长和急剧崩溃。在多孔硅的腐蚀过程中,由于超声波的作用增加了孔中氢气泡的逸出比率和塌缩,有利于孔沿垂直方向的腐蚀,使多孔硅光致发光峰的半峰全宽压缩到了3.8 nm。

The special physicochemical environment caused by sonic-vacating provides an important outlet for the preparation of highly efficient luminescent porous silicon （PS） films. Experiment results show that sonicchemical treatment is an effective technology for the improvement of the microstructure of porous silicon, the luminescent efficiency and stability thereof. Luminescent porous silicon films, prepared by ultrasonicenhanced anode electrochemical etching, display better qualities than the samples prepared by conventional methods widely used at present. This ultrasonic-chemical effect roots in sonic-vacating, i.e. the generation, formation and rapid collapse of bubbles in the etching solution. In the process of the PS being etched, the escape rate and caving-in of hydrogen bubbles in the pores is increased as a result of the work of the ultrasonic wave which is helpful to the vertical etching of the pores. It made full width at half maximum of porous silicon photoluminescence peak compress to 3.8 nm. In summary, we have presented an ultrasonic anodic etching method for fabricating light-emitting porous silicon material. Surface and cross-sectional SEM investigations reveal that when other etch parameters are constant, the ultrasonic etching creates a thicker and more uniform porous silicon layer, with smaller silicon pores than that of PS prepared by DC etching or pulsed etching. AFM observations further confirm the improved structural properties, which can be explained by the porous silicon formation mechanics especially by ultrasonic cavitation. The studies of both porous silicon single layer and porous silicon microcavity （PSM） show that ultrasonic etching optimizes the sample＇s optical characteristics. The best quality sample has been acquired by combining the ultrasonic etching with pulsed etching. This new etching method is an efficient technique to fabricate porous silicon materials, especially PSM, and opens a feasible way to realizing the application of porous silicon materials.