碲纳米线的电输运性能研究

发布时间：2018-08-09 15:39

【摘要】：碲,是一种重要的半导体材料,其禁带宽度为0.34 ev。碲的化合物纳米材料是非常重要的半导体光电材料,具有很优异的物理和化学性质,在半导体纳米器件和生物医学领域有广阔的应用前景。本文选取碲纳米线为研究对象,研究碲纳米线的电输运性能和光电特性。本文的主要研究工作如下:1.本文采用水热法合成了具有分散性良好、纯度高、结晶性好的单根Te纳米线,直径约为80 nm-200 nm。利用XRD和SEM分析手段对合成的碲纳米线进行表征,结果表明XRD图显示的最强峰[101]是碲纳米线的生长方向。2.采用深紫外曝光接触式光刻技术和金属剥离技术,构筑了基于单根Te纳米线的“金属/Te纳米线/金属”型半导体纳米器件。3.在室温下,测试了Te纳米线半导体器件分别在空气和真空中的电输运性能,结果表明金属电极和碲纳米线具有良好的欧姆接触。通过分析Te纳米器件的场效应特性曲线,发现漏电流Ids随着栅压Vgs的下降而减小,表明Te纳米器件是一个典型的P型半导体。实验还发现,空穴载流子的迁移率达到了750 cm2v-1s-1。随着相对湿度的增加,吸附在碲纳米线的表面的水分子数目增加,因此碲纳米线表面被水吸附的电子数也会相应增加,引起纳米线的表面电势降低,吸引更多的空穴到表面层。此种现象也会导致碲纳米线本身的电导增加。4.在不同波长的光照射下,发现Te纳米线具有负光电导现象。光生电子会吸附在纳米线的表面,并与其内部的空穴载流子复合,导致碲纳米线内部的空穴载流子浓度降低,故碲纳米线内部的空穴浓度是影响碲纳米线电导的未来希望通过测试碲纳米线在真空中的时间响应图,进一步验证上述碲纳米线的负光电导产生的机理。通过进一步研究可控制备碲纳米线的方法,为以后制备CdTe、Ag2Te、Bi2Te3等功能材料提供一个理想的模板。
[Abstract]:Tellurium, an important semiconductor material, has a band gap of 0.34 ev. Tellurium compound nanomaterials are very important semiconductor optoelectronic materials with excellent physical and chemical properties and have a broad application prospect in semiconductor nanodevices and biomedical fields. In this paper, tellurium nanowires are selected to study the electrical transport and photoelectric properties of tellurium nanowires. The main research work of this paper is as follows: 1. In this paper, single Te nanowires with good dispersion, high purity and good crystallinity have been synthesized by hydrothermal method. The diameter of Te nanowires is about 80 nm-200 nm. The synthesized tellurium nanowires were characterized by XRD and SEM analysis. The results show that the strongest peak [101] in XRD diagram is the growth direction of tellurium nanowires. The metal / Te nanowire / metal semiconductor nanodevices based on single Te nanowires were fabricated by using deep ultraviolet exposure contact lithography and metal stripping technology. The electrical transport properties of Te nanowire semiconductor devices in air and vacuum have been measured at room temperature. The results show that the metal electrodes have good ohmic contact with tellurium nanowires. By analyzing the field effect curves of Te nanodevices, it is found that the leakage current (Ids) decreases with the decrease of gate voltage Vgs, which indicates that Te nanodevices are a typical P-type semiconductor. It is also found that the mobility of the hole carrier reaches 750 cm ~ 2 v-1s-1. With the increase of relative humidity, the number of water molecules adsorbed on the surface of tellurium nanowires increases, so the number of electrons adsorbed by water on the surface of tellurium nanowires will increase accordingly, resulting in the decrease of surface potential of nanowires and the attraction of more holes to the surface layer. This phenomenon also leads to an increase in conductance of the tellurium nanowires. It is found that Te nanowires have negative photoconductivity under different wavelengths of light irradiation. Photogenerated electrons are adsorbed on the surface of nanowires and compound with hole carriers in the nanowires, resulting in a decrease in the hole-carrier concentration in tellurium nanowires. Therefore, the hole concentration in tellurium nanowires is the future of the conductivity of tellurium nanowires. It is hoped that the mechanism of negative photoconductivity of tellurium nanowires can be further verified by testing the time response diagram of tellurium nanowires in vacuum. The method of controllable preparation of tellurium nanowires is further studied to provide an ideal template for the preparation of functional materials such as CdTeO Ag2TeOBi2Te3 in the future.
【学位授予单位】：湖南师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O613.53;TB383.1

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