热蒸发SiO大量合成硅纳米线及其可控p型掺杂

Large-scale synthesis of silicon nanowires by thermal evaporation of silicon monoxide and controlled p-type doping

文章采用化学气相沉积法,以一氧化硅粉末为硅源,于1 350℃进行高温热蒸发,成功合成了大量单晶硅纳米线;并利用X-射线衍射、场发射扫描电子显微镜以及透射电子显微镜等手段对产物的形貌和微结构进行了系统表征。硅纳米线具有良好的结晶质量,直径在20～80 nm之间,长度为数十微米至数百微米,其外层通常为一层非晶硅氧化层所包裹。通过利用硼胶在高温下的扩散掺杂,进一步实现了硅纳米线的可控p型掺杂。针对单根硅纳米线器件的测量表明,硅纳米线的电导率可以从本征时的约10-7S/cm大幅提高到掺杂后的0.2 S/cm以上,且掺杂浓度可由扩散温度控制。此扩散掺杂方法简单有效,克服了氧化物辅助法生长硅纳米线电输运性质不易控制的难题,获得的p型硅纳米线有望应用于高性能硅纳米器件的研究。

Large-scale synthesis of single-crystalline Si nanowires was demonstrated by thermal evaporation of SiO at 1 350 ℃ via chemical vapor deposition（CVD） method.Morphologies and micro-structures of the product were systemically investigated by using X-ray diffraction（XRD）,field-effect scanning electron microscopy（FESEM）,and transmission electron microscopy（TEM）.The as-synthesized Si nanowires had good crystallinity with diameter in the range of 20～80 nm and length from tens of micrometers to hundreds of micrometers.Normally,the Si nanowires were covered by a layer of amorphous Si oxide via oxide-assisted growth（OAG） method.P-type doping to the Si nanowires was accomplished by thermal diffusion of B2O3 at high temperature.Electrical measurements on the single Si nanowires revealed that the conductivity of the nanowires could dramatically increase by B doping from about 10-7 S/cm for the intrinsic Si nanowires to above 0.2 S/cm for the B-doped Si nanowires.Also,the conductivity of the p-type Si nanowires could be precisely controlled by adjusting the diffusion temperature.This method is demonstrated to be simple and effective,which can overcome the difficulty in controlling the electrical properties of Si nanowires grown by OAG,thus offering the opportunities to fabricate high-performance nanodevices based on the p-type Si nanowires.