叉指电极中ZnO纳米棒网络状结构紫外探测器的研制

Using a low temperature hydrothermal synthesis method,ZnO nanorod networks have been directly grown across trenched Au microelectrodes arrays,which were modified with a layer of ZnO seeds.The characteristics of the current-voltage（I-V） and the photoresponse were obtained both in the dark and under ultraviolet illumination.The bridged nanorod network demonstrated a highly sensitive response to UV illumination in atmosphere at room temperature.It can be useful for nanoscale optoelectronic applications,serving as chemical sensors,biological sensors,and switching devices.     

氨化温度对Si基GaN纳米结构质量的影响(英文)

通过磁控溅射技术在Si(111)衬底上沉积Ga2O3/Co薄膜,然后在不同温度下氨化制得GaN纳米结构。采用X射线衍射(XRD)、傅里叶红外吸收谱(FTIR)、扫描电子显微镜(SEM)、高分辨透射电镜(HRTEM)和光致发光谱(PL)对样品的结构、形貌和光学特性进行了表征。结果显示合成的GaN纳米结构具有六方纤锌矿结构,且纳米结构的生长受温度影响很大。PL谱显示在388nm处有一强的紫外发光峰,表明其在低维激光器件方面的应用优势。同时对纳米结构的生长机制进行了简单讨论。     

ZnO纳米颗粒的紫外光探测器制备及其特性

为了发展高性能、低成本和结构简单的ZnO紫外 光探测器。在本文中,利用溶液法,制备出ZnO 纳米颗粒,采用透射电子显微镜(TEM)、X射线衍射仪(XRD)、紫外-可见分光光度计和荧光 光谱仪,分别 研究了ZnO纳米颗粒的形貌、晶相结构和光学特性。结果显示:样品呈球形状的颗粒,尺寸 分布在6~8.5nm 之间,平均粒径为7.1nm,为六方纤锌矿结构。发现ZnO纳米颗 粒的陡峭吸收边出现在370nm附近,在390nm 处出现一个很强的近带边发射峰和一宽泛的可见光发光带。此外,利用制备的ZnO纳米颗粒 ,旋涂在刻蚀 有叉指电极的FTO(SnO₂:F)上,制备出紫外光探测器,测试了它在暗态和365 nm紫外光照下的电流-电压(I-V) 和电流-时间(I-t)特性。结果表明:紫外光探测器的灵敏度、光响应度、响 应时间、恢复时间分别为62.4(在 －3.5V处),13.6A/W(在+5V处), 15s。另外,它的光响应机理主要由于ZnO纳米 颗粒表面吸附的氧起主导作用。     

Si基PIN光电探测器电场隔离结构对暗电流的影响

对Si基PIN光电探测器的电场隔离结构进行了研究,讨论了电场隔离结构的作用以及其与暗电流的关系,并进行了仿真模拟与测试分析.电场隔离结构主要将有源区和边缘隔离从而降低暗电流,结合仿真模拟结果和实验测试结果,分析得到电场隔离结构主要降低与周长有关的暗电流,对于小尺寸器件作用更明显.     

Si基纳米结构的电子性质

各种Si基纳米发光材料在Si基光电子器件及其全Si光电子集成技术中具有潜在的应用前景,从理论和实验上对其电子结构进行研究,有助于我们深化对其发光机制的认识与理解。本文主要从量子限制效应发光这一角度,着重介绍了Si纳米晶粒、Ge/Si量子点,SiO2/Si超晶格和超小尺寸Si纳米团簇等不同Si基纳米结构的电子性质以及它们与发光特性之间的关系。还讨论了介质镶嵌和表面钝化对其电子结构的影响。     

Si/Ge复合纳米结构的制备及表征

以Si和GeO2为原料,通过简单直接的热蒸发法在衬底的不同温度区域上得到了章鱼状、羽毛球状、拖把状等不同形貌的Si/Ge/O复合纳米结构。利用扫描电镜（SEM）研究了不同衬底区域纳米结构的形态,结合透射电镜（TEM）的明场像和扫描透射（STEM）模式下能谱的面扫描,系统地研究了不同形貌纳米结构的成分分布,并对生长过程进行了探讨。     

环境气氛对二维超薄ZnO纳米片紫外探测器性能的影响

二维宽带隙半导体材料独特的纳米结构是高性能紫外光电探测器的潜在理想材料,但是在实际应用过程中,各种环境气氛可显著影响紫外光探测器件的性能。文中采用化学气相沉积方法制备超薄二维ZnO纳米片,并利用该纳米片制作了紫外光探测器件。将探测器件置于密闭系统中进行测试,排除了不同应用环境对测试结果的影响,同时重点研究了不同极性分子对二维超薄ZnO纳米片紫外探测器性能的影响。研究结果表明,在极性分子存在的条件下,ZnO纳米紫外光探测器的暗电流降低1.5~2倍,灵敏性和响应率提高了约1.5倍。     

多孔硅负载银纳米颗粒提高硅基MSM光电探测器性能的研究

利用金属辅助刻蚀的方法在单晶硅片表面制备了多孔硅,结果表明多孔硅表面纳米结构的陷光作用在宽光谱范围内大幅提高了硅片的光吸收率。将银纳米颗粒负载到多孔硅表面,研究了其对硅基金属-半导体-金属型光电探测器(MSM-PDs)性能的影响。与基于硅片和多孔硅结构的MSM-PDs相比,基于多孔硅负载银纳米颗粒制备的MSM-PDs在420 nm入射光照射条件下的光暗电导比以及光响应度都有显著提高,这主要得益于表面纳米结构对暗电导的降低及光场中银纳米颗粒的LSPR效应对光电导的提升作用。     

激光分子束外延法制备AlN/Si异质结的电学性质

采用激光分子束外延法在Si(111)衬底上制备出沿c轴取向的AlN薄膜,在此基础上制备了Au/AlN/Si 金属 绝缘体 半导体(MIS)结构。研究了结构的电流传输机制、AlN/Si界面处的界面态密度值及分布情况。结果表明：AlN/Si异质结具有很好的整流特性,电流传输符合空间电荷限制传输机制,理想因子为2.88;结构的界面态密度约为1.1×1012 eV-1·cm-2,主要分布在距离Si衬底价带顶0.26 eV附近,由生长过程中引入的O杂质、N空位/N替代和Si原子代替N原子形成的Al-Si键组成。     

应用于深紫外波段的AlGaN光电探测器研究

本文报道了肖特基二极管深紫外光电探测器的制备.此器件制作在GaN外延层上,其中外延层利用金属有机化学汽相沉积(MOCVD)的方法生长在4in的Si(111)片上.利用光谱响应度测量法确定GaN的截止波长在近紫外波段(200～400 nm);在紫外波段(5～20 nm),利用位于Berliner Elektronen speicherring-Gesellschaft ftir Synchrotronstrahlung (BESSY)的PhysikalischTechnische Bundesanstah(PTB)设备完成了绝对光谱响应度测量与同步加速器辐射.此工作是在欧洲空间局(ESA)支持的盲区太阳探测器项目框架下完成的.     

Fabrication of ZnO nanowall-network ultraviolet photodetector on Si substrates

ZnO nanowall networks were prepared by plasma-assisted molecular beam epitaxy without a catalyst on Si(111) substrates.The nanostructures have preferred orientation along the c axis.The nanostructures are about 10 to 20 nm thick and about 50 nm tall.The planar geometry photoconductive type metal-semiconductor-metal photodetector based on the ZnO nanowall networks exhibits a high and wide response spectrum,and no decrease from 250 to 360 nm.With the applied bias below 5 V,the dark current was below 6μA,and the peak responsivity of 15 A/W was achieved at 360 nm.The UV(360 nm) to visible(450 nm) rejection ratio of around two orders could be extracted from the spectra response.     

Interface properties of ZnO nanotips grown on Si substrates

ZnO nanotips have been grown on Si (100) using metalorganic chemical vapor deposition (MOCVD). The growth temperature is optimized for good crystallinity, morphology, and optical properties. ZnO nanotips exhibit a strong near band edge emission of ∼376 nm at room temperature with negligible green band emission. Pregrowth substrate treatment using diluted hydrofluoric acid (HF) and minimized oxygen exposure before the initial growth significantly reduces the interfacial SiO₂ thickness, while maintaining good morphology. An n-ZnO nanotips/p-Si diode is fabricated and its I–V characteristic is measured. The threshold voltage of the diode is found to be below 2.0 V with small reverse leakage current. The ZnO/p-Si diodes provide the possibility of integrating the ZnO nanotips with Si-based electronic devices.     

ZnO/Ag 纳米线复合薄膜的光电导型紫外探测器

ZnO/Ag纳米线复合薄膜紫外探测器是利用水热法在旋涂制备的Ag纳米线薄膜上生长ZnO 纳米线阵列制备得到。此紫外探测器在4.9 mW cm_-2紫外光强和1V偏压下,其明暗电流比为3100,响应恢复时间分别为3.47s和3.28s,响应度为0.25A/W,探测度为6.9×10₁₂Jones。制备和工作参数被分析以优化紫外探测器结构和性能,如ZnO 纳米线的生长时间,Ag纳米线薄膜的旋涂转速和紫外探测器的工作温度。     

ZnO光电导紫外探测器的制备和特性研究

以Si(111)衬底,用脉冲激光沉积(PLD)法制得C轴高度择优取向的ZnO薄膜,并利用剥离技术制备了ZnO光导型紫外探测器.Al叉指状电极是由平面磁控溅射技术沉积得到的.对Al/ZnO/Al的伏安特性和紫外光响应的研究表明,金属铝和ZnO能形成很好的欧姆接触,紫外探测器的电阻值在100KΩ左右.在紫外区域,其5V偏压下的光响应度为0.5A/W.     

MBE growth and properties of ZnO on sapphire and SiC substrates

Molecular beam epitaxy (MBE) of ZnO on both sapphire and SiC substrates has been demonstrated. ZnO was used as a buffer layer for the epitaxial growth of GaN. ZnO is a würtzite crystal with a close lattice match (<2% mismatch) to GaN, an energy gap of 3.3 eV at room temperature, a low predicted conduction band offset to both GaN and SiC, and high electron conductivity. ZnO is relatively soft compared to the nitride semiconductors and is expected to act as a compliant buffer layer. Inductively coupled radio frequency plasma sources were used to generate active beams of nitrogen and oxygen for MBE growth. Characterization of the oxygen plasma by optical emission spectroscopy clearly indicated significant dissociation of O₂ into atomic oxygen. Reflected high energy electron diffraction (RHEED) of the ZnO growth surface showed a two-dimensional growth. ZnO layers had n-type carrier concentration of 9 × 10¹⁸ cm⁻³ with an electron mobility of 260 cm²/V-s. Initial I-V measurements displayed ohmic behavior across the SiC/ZnO and the ZnO/GaN heterointerfaces. RHEED of GaN growth by MBE on the ZnO buffer layers also exhibited a two-dimensional growth. We have demonstrated the viability of using ZnO as a buffer layer for the MBE growth of GaN.     

体晶ZnO光导探测器制备与测试

在体单晶ZnO的Zn面和O面通过直流溅射金属薄膜,并采用剥离电极成型方法制备梳妆电极,从而制备出体晶ZnO紫外光导探测器.对Pt/ZnO/Pt的伏安特性测试研究表明,金属Pt和ZnO形成很好的欧姆接触,而Zn面的器件电阻明显低于O面的器件电阻.对制成的紫外探测器的光电性能测试表明,器件制备极性面的选择,测试的调制频率、偏置电压对器件的性能有较大影响,最终器件的电流响应率达到14.6A/W.     

The investigation of Al-doped ZnO as an electron transporting layer for visible-blind ultraviolet photodetector based on n-ZnO nanorods/p-Si heterojunction

An n-ZnO nanorods/p-Si heterojunction photodetector with Al-doped ZnO (AZO) as an electron transporting layer was fabricated. The heterojunction with 20 nm AZO film showed a better characteristic than that of the device without AZO, and it displays a rectification ratio of 8470 at ±3 V and a turn-on voltage of 1.8 V. Also, based on spectral responsivity measurement, the device with AZO coating showed higher responsivity and better visible-blind detectivity than those without AZO, and the peak responsivity of the photodetector with AZO was as high as ~0.49 A/W at 354 nm. Furthermore, the photodetector with AZO layer showed a bigger UV–visible responsivity ratio (R_354 nm / R_546 nm) than that of the photodetector without AZO coating at −2 V. The role of AZO layer was illustrated through energy band theory and the electron transport mechanism.     

ZnO nanotips grown on Si substrates by metal-organic chemical-vapor deposition

The ZnO nanotips are grown on silicon and silicon-on-sapphire (SOS) substrates using the metal-organic chemical-vapor deposition (MOCVD) technique. The ZnO nanotips are found to be single crystal and vertically aligned along the c-axis. In-situ Ga doping is carried out during the MOCVD growth. The ZnO nanotips display strong near-band edge photoluminescence (PL) emission with negligible deep-level emission. Free excitonic emission dominates the 77-K PL spectrum of the as-grown, undoped ZnO nanotips, indicating good optical properties and a low defect concentration of the nanotips. The increase of PL intensity from Ga doping is attributed to Ga-related impurity band emission. Photoluminescence quenching is also observed because of heavy Ga doping. ZnO nanotips grown on Si can be patterned through photolithography and etching processes, providing the potential for integrating ZnO nanotip arrays with Si devices.     

硅(001)衬底上生长的ZnO薄膜的AFM研究

对采用电子束反应蒸镀方法在低温下在硅（001）衬底上外延生长的ZnO薄膜的表面构像进行了原子力显微镜（AFM）观察，分析研究不同的衬底温度对薄膜表面形貌及结构特性的影响。在250℃衬底温度下获得的ZnO薄膜，膜表面平整，结构致密，表面平均不平整度小于3nm，说明在该衬底温度下获得的ZnO薄膜是高透明度、高质量、高度取向的单晶薄膜。