GaSb纳米线的CVD可控制备及其光学表征

Controlled Synthesis of GaSb Nanowires Based on CVD-grown and Their Optical Characterization

采用CVD法合成Ga Sb纳米线,并分析生长时间对其长度的影响,随后对其进行光学表征.实验过程中,分别采用喷金法和滴金法对硅片进行预处理,再置于相同条件下制备Ga Sb纳米线;之后对其进行表征分析,根据扫描电子显微镜(SEM)表征结果证实,两种方法制备的纳米线都满足VLS生长机制.且发现Ga Sb纳米线的生长长度,可以通过改变其生长时间来进行控制.通过该纳米线的透射电子显微镜图(TEM)、X射线衍射图(XRD)等结构表征,表明该纳米线为结晶品质优良的立方闪锌矿结构;同时,从Ga Sb纳米线的拉曼光谱(Raman)及光致发光谱(PL)可以反映该纳米线具有优良的光学性质.由此证明,采用CVD法制得的纳米线光学性质优异,且可以实现可控制备.

Gallium antimonide （GaSb） has a relatively narrow band gap, high electron mobility and excellent saturation velocity, in addition, p-type GaSb nanowires （NWs） can be integrated with n-type nanowire devices potentially. These properties make it applicable both optically and electrically. However, it is noted that the radial dimensions and crystal quality have remarkable influence on the performance of photovoltaic devices. Based on traditional CVD technology, the influence of Au nanoparticles on Vapoure-Liquide-Solid （VLS） growth mechanisms has been studied, GaSb nanowires grown on two different substrates which undergo gold sputtering and gold solution dropping treatment have different geometries of seed particle on nanowire tip and shapes of its body, moreover, the contact angle between these two parts provides stable condition for nanowires growth which has considerable impact on growth direction. The entire growing process is divided into three phases by the temperature： the heating phase, the synthesis phase and the cooling phase. Controllable synthesis has been realized by fixing the synthesis temperature at 900 ℃ and keeping the other factors unchanged. In the meantime, changing the synthesis time from 60 minutes to 240 minutes in steps, it is found that the breakthrough in radial dimensions and specific surface has been realized with the increase of growing time, the GaSh nanowire of 50 μm has been achieved in this paper. Furthermore, the nanowires were systematically characterized by scanning electron microscope （SEM）, transmission electron microscope （TEM） and X-ray diffraction （XRD）, which suggest that this material has the zincblende structure with good crystal quality and high purity. Also, the Multi-mode phonon oscillation and band-edge emission of the nanowires are shown through Raman spectroscopy （Raman） and Photoluminescence Spectroscopy （PL）. All these demonstrate the superior surface morphology and good crystallinity of the obtained nanowires. The study makes contribution to the extensive exploration and novel discoveries of precise controllable growth of GaSb nanowires.