Fabrication and Characterization of 4H-SiC p-i-n Photodetectors

4H-SiC材料具有优越的电学性能，用于低电平的紫外线检测时，还具有可见光盲、在太阳盲光谱区域量子效率较高、低漏电流、抗辐射和耐高温等优点，本文制备并详细研究了4H-SiCp-i-n紫外光电探测器的光电性能，取得了以下重要的结果： 1.制备出高性能4H-SiCp-i-n紫外光电探测器，探测器的光敏面积为200×200μm2，封装在TO-2外壳上，用熔融石英玻璃作为光学窗口； 2.研究了4H-SiCp-i-n紫外光电探测器电容-电压（C-V）特性。结果表明探测器在0偏压时的高频（1MHz）结电容约为3.4pF并基本不随偏压变化，表明器件在较低偏压时i型层已基本处于耗尽状态。变温低频（100k...Silicon Carbide (SiC) has excellent physical, chemical and electronic properties. The ultraviolet (UV) photodetectors (PDs) based on 4H-SiC have the advantages of solar blindness to the background light, high quantum efficiency, low dark current, extremely radiation hardness, able to operate at high temperature and so on. In this dissertation, the high performance 4H-SiC p-i-n UV PDs has been fabr...学位：工学博士院系专业：物理与机电工程学院_微电子学与固体电子学学号：1982007015390

Effect on Photoluminescence Intensity of Porous Silicon Processing by a Wet Oxidized Technology

【中文文摘】在适当条件下氧化多孔硅是提高多孔硅发光强度的良好途径。首次采用含CH3CSNH2的HF酸水溶液作为氧化剂对初始多孔硅进行了湿法阳极氧化,大大改善了多孔硅的发光强度,并研究了氧化电流密度、氧化温度、氧化时间等一系列因素对氧化多孔硅光致发光强度的影响。实验发现,在电流密度1mA/cm2,氧化液温度60℃,氧化时间为10min的条件下,可以获得最强光致发光;在此最优条件下得到的氧化样品较初始样品发光增强了18倍。 【英文文摘】Oxidizing porous silicon in proper condition is a good approach to improve PS photoluminescence intensity.We for the first time using electrolyte containing CH_3CSNH_2 to oxidize initial PS,which boost up photoluminescence intensity of PS greatly.We also studied oxidizing current density,oxidizing temprature,oxidizing time etc.It is testified that the best intensity of PL can be obtained when oxidizing for 10 minutes in 60 ℃ oxidizing solution using 1 mA/cm~2 current density.In these conditions we can obtain best photolumine scence intensity which is 18 time s than that of original porous silicon

Photoluminescence Spectroscopy Studies of InGaAsN Quantum Wells

我们测量了低N组分的InGaAsN/InGaAs/GaAs量子阱材料的光致发光(PL)谱,测量温度范围从13K到300K。实验结果显示,InGaAsN的PL谱的主峰值的能量位置随温度的变化呈现出反常的S型温度依赖关系。用Varshni经验公式对实验数据进行拟合之后,发现在低温下InGaAsN量子阱中的载流子是处于局域态的。此外,我们还测量了样品在不同的温度、不同的能量位置的瞬态谱,结果进一步证实了:在低温下,InGaAsN的PL谱谱峰主要是局域态激子的复合发光占据主导地位,而且InGaAsN中的载流子局域态主要是由N等电子缺陷造成的涨落势引起的。The photoluminescence (PL) spectroscopy in InGaAsN/InGaAs/GaAs quantum wells (QWs) with low-nitrogen composition has been measured in the temperature range 13-300K. The peak position energies of InGaAsN as measured by PL exhibit anomalous inverted S-shape-like temperature dependence. Fitting with Varshni empirical relation to PL data, we have found that carriers in InGaAsN QWs are localized at low temperatures. Moreover, Time-resolved photoluminescence (TRPL) measurements, performed for various temperatures and different PL energy position, further proved that the broad PL emission of InGaAsN at low temperature is mainly dominated by strong localization, which arises from nitrogen-induced fluctuating potential in quantum wells

A New Type of Electromodulation Spectroscopy and Its Application

提出一种微接触电调制反射谱(LCER)测试方法,该方示与无接触电调制反射(CER)谱相比较,可极大降低调制电压。给出了自制的详细样品架结构,测量了InGaAs/GaAs量子阱样品,并与光调制反射谱(PR)相比较,结果证实了此方法的可行性和高光谱灵敏度,表明样品与电极的轻微接触既对测量结果没有明显的影响,又可简化测试条件,降低对测量环境的要求,是研究半导体材料和微结构一种方便而又有效的方法

Development of high-sensitivity preamplifier of surface photovoltaic spectroscopy

表面光伏技术可测量半导体材料的少数载流子的扩散长度、表面电荷等,能表征半导体微结构。采用静电计管作为信号的前置放大器具有电压增益低、体积大等缺点。介绍了一种表面光伏谱前置放大器的设计原理、设计方案和应用实例。该前置放大器具有灵敏度高、响应时间短、截止频率低等优点,并且体积小、使用成本低。The paper introduces the design and application of a new kind of surface photovoltaic spectroscopy preamplifier.This preamplifier has not only advantages of high sensitivity,low response time,low cut-off frequency,but also smaller size and lower price.厦门大学科技创新项目(Xdkjcx20061028)专利号(ZL00620156385.1

Research and fabrication of silicon based metal-semiconductor-metal photodetector with U-shape trench interdigitated electrodes

为了提高硅MSM结构光电探测器的光电响应度,制备了U型凹槽电极结构的探测器。5 V偏压下,对650 nm波长入射光的绝对光电响应度测试表明,凹槽电极结构的探测器最大光电响应度值为0.486 A/W,比同样尺寸的平版结构光电探测器提高了约6倍。文中也对比了具有抗反射膜和不具有抗反射膜的器件相对响应光谱的差别,并且比较分析了叉指间隙分别为5μm和10μm器件光电响应的不同。The responsivity of silicon based metal-semiconductor-metal(MSM) photodetector(Si-MSM-PD) was improved by placing the planar interdigitated electrodes with U-shape trench interdigitated electrodes.The performance test indicates that the responsivity of Si-MSM-PD with U-shape trench interdigitated electrodes is 0.486 A/W for 650 nm laser at 5 V applied voltage.This responsivity is about 6 times larger than that of Si-MSM-PD with planar interdigitated electrodes whose responsivity is just 0.084 A/W.Besides,the performance of Si-MSM-PDs with different intergitated space of 5 μm and 10 μm was compared.国家自然科学基金资助项目(60576001,60336010,60676027);; 福建省自然科学基金资助项目(A0410008

XPS Dissection of the Optical Transition Additive in Farm Film

报道了无保护气氛条件下,采用高温固相还原法合成适用于农用塑料地膜的光转换添加剂,共掺铜、铕激活剂的硫化钙(CaS)无机荧光材料,用X射线光电子能谱(XPS)方法对光转换添加剂中不同工艺下激活剂元素进行表征,再通过光致发光谱、透射光谱测量,探索材料中激活剂的能量传输特性,为高新农业的发展提供清洁能源。An optical transition additive used in farmfilmwas synthesized by doping the Cu and Eu activators into an inorganic fluorescent material,CaS with the high-temperature solid phase reduction method under unˉprotected atmosphere.The characteristics of the activators in the films prepared under different conditions were measured by X-ray photo-electron spectroscopy.The energy-transfer properties of the activators in the films were investigated by the photo-induced luminescence spectra and transmission spectra.It is useful for developing a clean energy source in agriculture.福建省自然科学基金资助项目(A0110006);; 厦门大学自选课题基金资助项目(Y07007

Photoluminescence of Multilayer InAs Quantum Dots

采用MBE设备生长了多层InAs/GaAs量子点结构,测量了其变温光致发光谱和时间分辨光致发光谱。结果表明多层量子点结构有利于减小发光峰的半高宽,并且可以提高发光峰半高宽和发光寿命的温度稳定性。实验发现,加InGaAs盖层后,量子点发光峰的半高宽进一步减小,最小达到23.6 meV,并且发光峰出现红移。原因可能在于InGaAs盖层减小了InAs岛所受的应力,阻止了In组分的偏析,提高了InAs量子点尺寸分布的均匀性和质量,导致载流子在不同量子点中的迁移效应减弱。Multilayer InAs/GaAs quantum dots structures were grown by molecular-beam epitaxy(MBE).The steady-state and time-resolved photoluminescence of the samples were measured at various temperatures.Results showed that multilayer structures could not only narrow the photoluminescence FWHM(full width at the half maximum) but enhance the stability of the photoluminescence lifetime and FWHM.As for the quantum dots with InGaAs cap layer,the photoluminescent spectra became narrower(the narrowest FWHM was only 23.6meV) and the photoluminescent wavelength became longer.The possible reason for the above phenomena was that the InGaAs cap layer could both release the strains in InAs islands and inhibit segregation of In components,resulting in the weaker migration among different quantum dots

Research progress in 4H-SiC-based ultraviolet photodetectors

介绍了4H-SIC材料用于高温、低电平紫外光电检测的优点,回顾总结了近年来4H-SIC基紫外光电探测器的研究进展,分析了改善4H-SIC基紫外光电探测器性能参数如降低暗电流、提高光电响应度等可采用的各种技术手段,探讨了4H-SIC基紫外光电探测器的发展趋势。Advances in 4H silicon carbide(4H-SiC) as a potential material for low-level ultraviolet(UV)radiation detection application at high-temperature,radiation hardened conditions are introduced.The latest progress in development of and the current state-of-art of different types of 4H-SiC-based UV photodetectors are reviewed.The approaches to improve the performances of the 4H-SiC-based photodetectors such as reducing the dark current and enhancing the photo responsivity are presented.The outlook for the development of 4H-SiC-based UV photodetectors are discussed.国家自然科学基金(61176049

New Anodic Oxidized Technology OF Porous Silicon

【中文文摘】在适当条件下氧化多孔硅是提高多孔硅发光强度的良好途径,提出了一种新型阳极氧化方法,并探讨了该方法所涉及的阳极氧化条件。采用含CH3CSNH2的HF酸水溶液作为氧化剂对初始多孔硅进行了湿法阳极氧化,发现氧化使多孔硅光致发光性质得到极大改善,进而研究了氧化电流、氧化温度、氧化时间等一系列因素对氧化多孔硅光致发光强度的影响,并给出了合理解释。实验发现,在1mA,10min,60℃的氧化条件下,采用阳极氧化技术使多孔硅发光强度增强了18倍。 【英文文摘】Oxidizing porous silicon in proper condition is a good approach to improve PS photoluminescence intensity.The article for the first time raised a new anodic oxidized technology of PS.We used electrolyte containing CH_3CSNH_2 to oxidize initial PS, and found that this method can improve the quality of photoluminescence, it can not only enhance the PL intensity greatly, but also increase the photoluminescence stability. Then we studied the oxidizing conditions(current, time, temperature etc.)which affect photoluminescence intensity and stability of PS and gave reasonable explanations. The small oxidizing current can repair the nanostructure of PS , the appropriate oxidizing time can limit the probability of nonradiative recombination , while the optimum oxidizing temperature is propitious to the transit of charge which can make the concentration of electrolyte balanceable , hence , the photoluminescence of oxidized PS is improved evidently. We discovered that the anodic oxidized technology of PS made the integral intensity of photoluminescence enhanced 18 times when in the optimum oxidized conditions of (1mA ,10 min ,60 ℃)国家重点自然科学基金资助项目(60336010