采用脉冲阳极 /阴极电流和化学氧化两步法分别在 1∶1的氢氟酸和乙醇溶液中及 2 0 %硝酸溶液中制备出孔径约为 0 .5～ 3μm ,厚度大约为 10～ 2 0 μm的多孔硅样品 ,将获得的多孔硅结构再进一步用扫描电子显微镜和拉曼光谱仪进行表面形貌和光学性质的考察 .与恒电流 -化学氧化两步法制得的多孔硅相比 ,用脉冲电流法得到的多孔硅的孔径范围较大 ,且多孔层较厚 .制备时加紫外光照显著提高了多孔硅的厚度 ,并发生“蓝移”现象 .用脉冲电流法制得的多孔硅在老化后 (在干燥器放置一年 )同样观察到光致发光明显增强 .

Porous silicon structures were formed by two?step technique consisting of pulse current applications in 1∶1 hydrofluoric acid and ethanol solutions and chemical oxidation in 20% nitric acid solutions. Their surface morphologies and optical properties were characterized by scanning electron microscope (SEM) and Raman spectrometer, and compared with those obtained by constant current application. More uniform pore formation on p(100) silicon wafers was observed by pulse current application. Illumination with an ultraviolet lamp during the pulse current application accelerated the macropore formation, accordingly, the optical properties were changed.