Al掺杂ZnO紫外探测器的快速响应技术

通过交变电场下的紫外光响应测试,观察到ZnO基薄膜在254 nm紫外光激发下的慢响应现象,并测量了响应时间常数。为提高ZnO基薄膜紫外探测器的性能,采用磁控溅射法,制备了纯ZnO薄膜和掺Al浓度为10 at.%(原子比例)的ZnO薄膜紫外探测器,测量了样品的频率特性曲线。结果表明,Al掺杂能有效地抑制ZnO薄膜的慢响应,实现探测器对紫外光的响应时间常数τ<25μs的快速响应。     

紫外探测器及其研究进展

最近,人们越来越关注紫外光的辐射与测量。本文主要介绍了紫外探测器的原理和研究现状。     

GaN基紫外探测器及其研究进展

宽禁带半导体材料的研究和突破,带动了各种器件的发展和应用。GaN基紫外探测器具有通过调整材料的配比可以调节器件响应的截止波长的优点,可以制备日盲型紫外探测器。对GaN基宽禁带紫外探测器材料体系的研究进展进行了回顾,重点介绍了p型材料的制备、金属半导体接触、材料的蚀刻等。最后,对国内外近期的紫外探测器特别是紫外焦平面器件的研究进展及初步获得的32×32紫外焦平面探测器进行了简单介绍。     

ZnO基紫外探测器及其研究进展

介绍了ZnO基紫外探测材料的主要制备方法、特性以及器件的最新研究进展,并简要分析了今后的发展方向。     

氧化物基紫外探测器的研究进展

随着紫外探测技术的不断发展,氧化物材料在紫外探测领域表现出传统探测器所不具备的优点而成为近年研究的热点,是继红外探测技术之后又一快速发展的军民两用探测技术。然而,氧化物基紫外光电探测器的广泛应用,仍然面临一些问题。本文对国内外紫外探测技术的应用和发展历史进行了概述,并对3种金属氧化物紫外探测材料的晶体结构、性质及其器件研究进展进行了概括和讨论。最后,针对氧化物基紫外探测材料及器件在研究中所面临的问题,进行了分析,并对氧化物基紫外探测技术的发展进行了总结与展望。     

氧化锌的p型掺杂改性研究进展

综述了近年来纳米氧化锌材料p型掺杂改性的研究现状,介绍了用于p型掺杂的单元素和共掺杂双元素以及所采用的主要掺杂方法,这些方法包括热蒸发法、喷雾热解法、溶胶-凝胶法、低温水解法、离子束增强沉积法、脉冲激光沉积法和磁控溅射法等。探讨了掺杂后的氧化锌在光电磁以及p型稳定性等方面表现出的新特性,介绍了p型氧化锌薄膜在紫外探测器和太阳电池方面的应用,对p型氧化锌薄膜未来的发展进行了分析和预测,认为制备稳定、低电阻率和高载流子浓度的p型氧化锌薄膜是今后研究的重点。     

GaN基半导体太阳盲区紫外探测器研究进展

基于半导体紫外光探测器的基本类型，在对半导体紫外探测器的研发历史进行简要回顾的同时，综述了各种形式GaN基紫外探测器的研究开发现状，并报道了GaN基宽带半导体太阳盲区紫外光探测器研究新进展。     

Ⅲ族氮化物紫外探测器及其研究进展

文中简单介绍了紫外波段光电探测的基本特点,包括各波段特点、大气吸收等,并粗略 介绍了紫外探测的部分应用。然后对Ⅲ族氮化物宽禁带紫外探测器材料体系的研究进展进行了回顾,重点介绍了包括P型材料的制备、金属半导体接触、材料的蚀刻等方面;最后,对国内外近期的紫外探测器特别是紫外焦平面器件的研究进展作了一些评述。     

基于GaN的紫外探测器线列

美国哥达德空间飞行中心最近研制了一种基于氮化镓的紫外探测器线列,这种紫外探测器线列对大部分可见光光谱是盲目的,其截止波长为370 nm.它能在存在大量可见光辐射的情况下进行紫外光成像,而无需用大面积的挡板来抑制杂散光或者用昂贵的滤光片来阻挡可见光.该GaN探测器列阵的体积、重量及功耗比现在用于深测紫外光的光电倍增管和微道板低一个数量级,它还能够在较低的电压下工作.此外,GaN材料比较坚固,用它制备探测器比较容易.     

紫外通信中探测器的研究

紫外光由于具有日盲特点而使其在通信方面有着特殊的的必要性及优越性,紫外光的探测是紫外光通信和其他常用通信方式的主要区别点。介绍了几类现有的应用于日盲紫外光通信系统的日盲紫外探测器,并对其光谱响应,量子效率等特点进行了分析,得出了各类紫外探测器的适用条件,为器件的选取提供一定的参考并进一步探讨了紫外探测器的发展趋势。     

Bidirectional and Dual-Mode Organic Photodetector Enables Secure Ultraviolet Communication

Traditional optical communication mode with single-band photodetector depicts terrible confidentiality and it depends on sophisticated cryptography schemes to obtain a secure communication process. Dual-band photodetectors have potential to realize a secure optical communication with a straightforward optical encryption strategy. However, previous reports of dual-band organic photodetectors (OPD) relied on the multi-stacked photosensitive layers thus there remain challenges in spectral matching and interfaces contacting. Here, a structurally simple bidirectional and UV–vis dual-band OPD is proposed, with single photosensitive layer sitting between electrodes. By elaborately regulating the optical field distribution and vertical phase segregation of the bulk heterojunction (BHJ), this OPD presents completely distinct spectral response ranges under bidirectional illuminations. Finally, this OPD outputs outstanding self-powered UV and vis dual-band responsivities (up to 30 and 50 mA W⁻¹) as the light illuminates from forward and backward direction, respectively. In addition, a stable and reliable optical communication system is realized based on this OPD where the UV response conveys valid information and further superimposes vis response for encryption. This design concept offers a simple alternative for achieving varied response windows and opens up a novel optical encryption method, which has potential be applied in a close-range private communication process.     

High‐Performance Ultraviolet Photodetector Based on a Few‐Layered 2D NiPS3 Nanosheet

2D materials, represented by transition metal dichalcogenides (TMDs), have attracted tremendous research interests in photoelectronic and electronic devices. However, for their relatively small bandgap (<2 eV), the application of traditional TMDs into solar‐blind ultraviolet (UV) photodetection is restricted. Here, for the first time, NiPS₃ nanosheets are grown via chemical vapor deposition method. The nanosheets thinning to 3.2 nm with the lateral size of dozens of micrometers are acquired. Based on the various nanosheets, a linearity is found between the Raman intensity of specific A_g modes and the thickness, providing a convenient method to determine their layer numbers. Furthermore, a UV photodetector is fabricated using few‐layered 2D NiPS₃ nanosheets. It shows an ultrafast rise time shorter than 5 ms with an ultralow dark current less than 10 fA. Notably, this UV photodetector demonstrates a high detectivity of 1.22 × 10¹² Jones, outperforming some traditional wide‐bandgap UV detectors. The wavelength‐dependent photoresponsivity measurement allows the direct observation of an admirable cut‐off wavelength at 360 nm, which indicates a superior spectral selectivity. The promising photodetector performance, accompanied with the controllable fabrication and transfer process of nanosheet, lays the foundation of applying 2D semiconductors for ultrafast UV light detection.     

sol-gel法制备表面改性纳米氧化锌

采用Zn(NO3)2.6H2O和NH3.H2O及合适的表面改性剂,通过sol-gel前驱体法,制备了高纯度的纳米ZnO粉体。采用激光粒度分析、SEM、XRD等手段,对所制备的粉体进行了表征。并研究了主盐浓度、反应温度、反应体系的pH值、表面改性剂等因素对ZnO晶体形成过程和显微结构的影响。结果表明:在Zn2+浓度为0.1mol/L、反应体系温度为50℃、pH值为6.0,采用聚乙二醇(PEG-2000)作为表面改性剂,将制得的前驱体在400℃分解2h,获得了纯度高、分散性好、结晶完整、粒度分布窄、粒状的纳米ZnO粉体。     

New Ultraviolet Photodetector Based on Individual Nb2O5 Nanobelts

Although human eyes are quite insensitive to ultraviolet (UV) light, most of the longer wavelength UV light (the UV‐A band between 320 and 400 nm) does reach the earth surface and after prolonged exposure, the radiation can cause health concerns especially skin cancer. Therefore, it is extremely important to explore ways to effectively monitor the radiation. Herein we report for the first time a new high‐performance UV photodetector made of an individual Nb₂O₅ nanobelt. Quasi‐aligned Nb₂O₅ nanobelts 100–500 nm wide and 2–10 μm long were synthesized using a hydrothermal treatment of a niobium foil in a KOH solution followed by proton exchange and calcination treatment. A nanostructured photodetector was constructed from an individual Nb₂O₅ nanobelt and its optoelectronic properties were evaluated. The detector exhibited linear photocurrent characteristics, excellent light selectivity, and high external quantum‐efficiency (EQE) of 6070%. Long‐term stability of the photocurrent over a period of 2500 s at an applied voltage of 1.0 V was achieved. The photodetector performance was further enhanced by improving the crystallinity and eliminating the defects in the Nb₂O₅ nanobelt crystals. These excellent optoelectronic properties demonstrate that Nb₂O₅ nanobelts are suitable for visible‐blind UV‐light sensors and optoelectronic circuits, especially those operating in the UV‐A range.     

A Back-Illuminated Vertical-Structure Ultraviolet Photodetector Based on an RF-Sputtered ZnO Film

A back-illuminated vertical-structure ZnO ultraviolet (UV) detector was fabricated using an indium-tin oxide (ITO) electrode. Ordered ITO and ZnO films were grown on a quartz substrate by radiofrequency sputtering. At 5 V bias, the dark current was 640 μA and the photocurrent was 16.8 mA under UV illumination (365 nm, 10 μW), indicating a high responsivity of 1616 A/W. The response time measurements showed a rise time of 71.2 ns and a decay time of 377 μs. The ZnO detector performed well and can be used in a focal-plane array for UV image detection.     

Cu掺杂氧化锌氧化物的热学性能

基于线性响应的密度泛函微扰理论研究了Cu掺杂纤锌矿结构氧化物ZnO的热学参数和热学性能。结果表明,Cu掺杂导致ZnO氧化物晶胞减小;在计算温度区间,纯的ZnO和Cu掺杂的ZnO的晶格热容均随温度升高不断增大,Cu掺杂的ZnO具有较高的晶格热容;纯的ZnO和Cu掺杂ZnO的晶格热容在最高温度900K时分别达到69.1J·(mol-1·K-1)和152.8J·(mol-1·K-1)。纯的ZnO和Cu掺杂ZnO的德拜温度均随温度升高而不断增大;在175K以下,Cu掺杂ZnO体系的德拜温度高于未掺杂体系,在175K以上,Cu掺杂ZnO体系的德拜温度低于未掺杂体系。Cu掺杂在ZnO中引入了新的振动模式。Cu掺杂ZnO氧化物应具有较高的晶格热导率。     

Ultraviolet detectors based on epitaxial ZnO films grown by MOCVD

High-quality zinc oxide (ZnO) films were epitaxially grown on R-plane sapphire substrates by metalorganic chemical vapor deposition at temperatures in the range of 350°C to 600°C. In-situ nitrogen compensation doping was performed using NH₃. Microstructural and optical properties of the films, as well as the N-doping effects, were studied. The metal-semiconductor-metal ultraviolet sensitive photodetectors were fabricated on N-doped epitaxial ZnO films. The detector showed fast photoresponse, with a rise time of 1 μs and a fall time of 1.5 μs. Low-frequency photoresponsivity, on the order of 400 A/W at 5 V bias, was obtained.     

基于NPB和Bphen的有机紫外探测器件的性能研究

有机紫外光探测器(Organic Ultraviolet Photodetector,OUV-PD)因质量轻、柔性和成本低等优点已引起广泛关注.以m-MTDATA、NPB和Bphen分别为空穴注入层、给体和受体制备了OUV-PD.器件结构为:ITO/m-MTDATA/NPB/Bphen/LiF/Al,通过优化给受体层的厚度,实现了器件的最优性能.当NPB厚度为60 nm、Bphen厚度为90 nm时器件性能最佳,在光照强度为1.05 mW/cm2、波长为365 nm的紫外光照射下,最大响应度为131 mA/W.同时,结合材料特点和器件结构讨论了工作机理.     

纳米微晶结构氧化锌中激子发光的研究进展

由于ZnO具有大的激子束缚能,有利于在室温下获得高效稳定的紫外辐射.因此,对ZnO激子发光的研究极有希望解决半导体照明、紫外半导体激光器等多种技术面临的瓶颈问题.综述了ZnO中激子的典型光致发光谱、激子的结构及复合发光过程.重点介绍了温度、激发功率、量子限域效应以及激光辐照等因素对ZnO激子发光的影响.     

A High-Performance Ultraviolet Photoconductive Detector Based on a ZnO Film Grown by RF Sputtering

A high-performance metal-semiconductor-metal (MSM) ultraviolet photodetector was fabricated based on a ZnO film with Al interdigitated (IDT) electrodes. A c-axis-oriented ZnO film was grown on a SiO₂/Si (100) substrate at room temperature by a reactive radiofrequency (RF) sputtering technique and then annealed at 900°C in pure O₂ ambient for 1 h. The fabricated ZnO ultraviolet (UV) detector demonstrated a high responsivity of 2069 A/W when biased at 5 V, which could be attributed to the influence of the annealing process in pure O₂ ambient. The response time measurement showed a rise time (10–90%) of 45.1 ns and a decay time (1 − 1/e) of 541 μs.