【摘要】 通过化学气相沉积方法(CVD)制备了In-Al共掺杂的氧化锌纳米串.扫描电镜观察到纳米片沿生长方向均匀排列,直径约为50~150 nm,长度约为5~20 μm.X射线衍射结果表明样品具有ZnO六角纤锌矿结构.并且研究了In-Al共掺杂的氧化锌纳米串的生长机制,并通过样品的光致发光谱可见所合成的样品具有较好晶体质量.
【关键词】 氧化锌;纳米串;光致发光
0引言
目前半导体纳米材料已备受瞩目,其中ZnO作为一种直接带隙宽禁带(Eg=3.37 eV)半导体材料是最为引人注意的材料之一[1-3].通常通过控制纳米材料的尺寸、结构或对ZnO纳米材料有效的掺杂,能够对其物理性质进行改善和调整.对其进行适当的掺杂(如在ZnO中共掺Ⅲ族和Ⅴ族元素)可实现ZnO的导电类型从n型到p型的转换,也可以使得ZnO纳米材料的光学电学性能有着显著的提高,所以研究对ZnO的有效掺杂是非常必要的.
该文重点研究了In-Al共掺杂ZnO纳米串的制备,并结合扫描电子显微镜、X射线衍射仪等仪器对样品的形貌、结构进行表征.观察到纳米片沿其生长方向相互平行排列,并研究了纳米串的生长机制.ZnO纳米串的光致发光性质,显示其具有较好的结晶质量.
1实验过程
应用CVD法合成In-Al共掺杂的ZnO纳米串:取ZnO、InN和Al粉的混合物(ZnO:0.5 g,InN:0.1 g,Al:0.1 g)作为前驱物,用于纳米材料的生长,并放在刚玉舟上置于高温炉的中心位置.将单晶Si (100片)摆放在源的下游,作为接收材料的衬底.以N2 作为载气,流速为200 sccm.加热,反应室压强保持在500 Pa,反应室的温度升温至1300 ℃,保持在这个温度下20 min.然后反应室温度自然冷却到室温,取出高温区样品,此样品距前驱物中心约26 cm,对此样品进行表征和光学性质测试.
3结论
通过简单的CVD方法合成了In-Al共掺杂的ZnO纳米串.通过SEM、TEM等测试方法对样品进行了表征,XRD谱证实样品具有ZnO六角纤锌矿纳米结构.纳米串通过两个阶段形成:通过VLS生长机制形成纳米线;接着在纳米线表面成核、垂直于纳米线外延生长纳米片;随后通过Ostwald熟化过程,形成In-Al共掺杂ZnO纳米串.In-Al共掺杂的ZnO纳米串的光致发光谱显示出所合成样品具有较强的紫外发射,预示着这种材料在短波光电子器件中的将会有一定的应用潜力.
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Abstract:
In this paper, In-Al doped ZnO nanobunches is fabricated by chemical-vapor deposition (CVD). Platelets are regularly arrayed along the direction of growth by scanning electron microscopy. Their diameter and length are 50~150 nm and 5~20 μm, respectively. The nanobunches have wurtzite ZnO structure by XRD data. A possible growth mechanism has been discussed and the photoluminescence confirm that nanobunches have a good crystal quality.
Keywords: ZnO; Nanobunches; Photoluminescence
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