【摘要】 在氮气气氛和常压下,采用无金属催化的单步热气相法在单晶硅片上制备大量纯非晶氧化硅纳米线,采用SEM、HRTEM、EDS、XRD和荧光光谱(PL)研究氧化硅纳米线形貌、结构和光致发光性质,并分析其发光中心。结果表明1100℃可形成纳米棒,1200℃则获得光滑均匀纳米线,而1300℃得到的纳米线具有较多弯曲结构,氧化硅纳米线中硅氧原子比接近1∶2,且1300℃制得纳米线中氧含量略高于1200℃,氧化硅纳米线呈无定型态。SiO气化分解和氧化时在硅片上形成氧化硅纳米簇,成为无定形氧化硅纳米线生长的成核中心。氧化硅纳米线的两个光致发光峰值波长为467和364nm,其发光机制是纳米线生长过程中产生的不同点缺陷结构构成了蓝光和紫外光辐射复合中心。更多还原

【Abstract】 A large quantity of silica nanowires were prepared by a non-catalytic and single-step thermal vapor method using polished p-Si wafers as substrates under nitrogen ambient at atmospheric pressure.Scanning electron microscopy(SEM) equipped with energy dispersive X-ray spectrometry(EDS),high-resolution transmission electron microscopy(HRTEM) and X-ray diffractometry(XRD) were used to characterize the morphology and structure of the product.The results indicated that silica nanorods were obtained at 1100℃,and smooth and uniform nanowires were observed at 1200℃ while nanowires with many curved segments at 1300℃.The EDS analysis indicated that nanowires consisted of mainly Si and O in an atomic ratio of about 1∶2 corresponding to SiO2.The XRD patterns and HRTEM study revealed amorphous character of the as-grown nanowires.Fine SiO2 cluster,which was formed by disproportionation and oxidation of SiO vapors,acts as nucleation centers for silica nanowires growth.Photoluminescence spectra of the silica nanowires recorded with 270nm excitation showed two broad peaks of ultraviolet(UV) and blue light emissions centred at 364 and 467nm,respectively.The blue and UV luminescence were attributed to the various structural defects in silica nanowires,which might have been generated during the nanowires growth.更多还原