GaAs基谐振腔增强型光电探测器

本文报道了利用MBE和MOCVD方法生长外延材料并制作出GaAs基谐振腔增强型光电探测器，进行理论分析和实验研究的结果。     

基于1.06μm波长的谐振腔型石墨烯光电探测器的信噪比分析

雪崩光电二极管由于具有高增益特性而广泛应用于激光测距机中,但由于在电流倍增过程中引入的高附加噪声,使激光测距机进一步提高信噪比遇到了瓶颈。石墨烯具有高电子迁移率、零带隙结构、独特光吸收系数等特性使其广泛应用于激光器、光调制器、透明电极以及超快光电探测器。该研究提出了一种高信噪比的谐振腔型石墨烯光电探测器的设计方法。以波长为1.06μm的激光为例,采用光学传输矩阵法和散射矩阵法,研究了光波在谐振腔传输和吸收层吸收的机理,建立了谐振腔型光电探测器的光吸收模型,通过优化,器件最终量子效率达到91.2%,响应度达到0.778A·W~(-1),半高全宽达到6nm;分析石墨烯在谐振腔中的位置对器件吸收率的影响,发现在满足谐振条件下,器件吸收率随石墨烯位置呈现周期性变化,腔长的改变不改变吸收率峰值,而是改变了吸收率峰值对应的石墨烯在谐振腔中的位置,当腔长是入射光半波长的n倍时,随着石墨烯位置变化,将出现2n个吸收率峰值,且关于谐振腔中心点对称分布;选择石墨烯距顶层反射镜0.402 8μm时,器件吸收率达到94%,相比单层石墨烯,吸收率提高了16dB;通过对比求解谐振腔型石墨烯光电探测器和雪崩光电二极管信噪比方程,得出谐振腔型石墨烯光电探测器信噪比可达到90.3,较雪崩光电二极管提高了10dB;理论分析表明,谐振腔型石墨烯光电探测器具有高吸收率、高量子效率和高信噪比,研究成果将对激光测距机接收系统中光电探测器的更新设计和应用提供理论参考。     

不同响应机制下的石墨烯基光电探测器研究进展

光电探测器因可将光信号转换为电信号而被广泛地应用于视频成像、光通信、生物医学成像和运动检测等方面.但由于所采用的传统光电探测器材料对其性能带来的局限性和日益增长的新需求之间的矛盾,使得寻找新的材料迫在眉睫.近年来新兴的二维材料为制备更高性能的探测器提供了全新的材料研究平台,其中石墨烯以其独特的电学、光学与热学特性成为下...     

谐振腔增强型光电探测器的角度相关特性研究

采用MBE生长In_0.3Ga_0.7As/GaAs和GaInNAs/GaAs量子阱为有源区的器件结构材料,制备出工作在1060nm及1310nm波段的谐振腔增强型光电探测器.对谐振腔增强型光电探测器的空间角度相关特性进行了实验与物理分析,改变光束入射角度,器件谐振接收波长可在大范围调变.     

基于石墨烯-钙钛矿量子点场效应晶体管的光电探测器

以等离子增强化学气相沉积法制备的石墨烯作为导电沟道材料,将其与无机CsPbI_3钙钛矿量子点结合,设计并制备了石墨烯-钙钛矿量子点场效应晶体管光电探测器.研究和分析了石墨烯作为场效应晶体管的电学特性及其与钙钛矿量子点结合作为光电探测器的光电特性.结果表明,石墨烯在场效应晶体管中表现出良好的电学性质,其与钙钛矿量子点的结合对波长为400 nm的光辐射具有明显的光响应,在光强为12μW时器件光生电流最大为64μA,响应率达6.4 A·W~(-1),对应的光电导增益和探测率分别为3.7×10~4,6×10~7Jones(1 Jones=1 cm·Hz~(1/2)·W~(-1)).     

基于石墨烯的半导体光电器件研究进展

石墨烯自从被发现以来,由于其零带隙、低电导率、常温下的高电子迁移率及量子霍尔效应和独特的光吸收等优良特性,引发了世界各国科研人员的重视,研究人员对其物理性质及应用的研究越来越多并且进展迅速．本文以光纤通信用光电器件中的探测器、调制器为主,综述了石墨烯在光电探测器、调制器以及超快锁模激光器和用于发光二级管、触摸屏透明导电薄膜等方面的应用．     

石墨烯/硅光电探测器的I-V及C-V特性

设计并制备了基于石墨烯/n型硅肖特基结的光电探测器,并从能带角度研究和分析了其I-V及C-V特性。结果表明,石墨烯/氮化硅/硅(金属-绝缘层-半导体)电容器对器件的I-V及C-V特性有较大影响。在808nm近红外光的照射下,器件反向电流和正向电流大小接近,归因于氮化硅/硅界面堆积的光生空穴向石墨烯/硅肖特基结的扩散,器件光响应度为0.26A/W。基于热发射模型从I-V暗电流曲线提取的肖特基势垒高度及理想因子分别为0.859eV和2.3。利用肖特基二极管耗尽层电容公式从C~(-2)-V曲线提取的势垒高度随着频率的增加而增加并趋于稳定在0.82eV。由于界面态的影响,石墨烯/硅肖特基结耗尽层宽度随频率增加而增加,而硅施主原子的掺杂浓度及器件电容则随频率增加而减小。     

等离激元增强型光电探测器

西班牙的一支研究团队已制造出了一种将等离激元透镜与胶状量子点活动区域结合起来的小而灵敏的光电探测器。巴塞罗那光子科学研究所的西尔克·迪登霍芬(Silke Diedenhofen)及其同事利用由胶状Pb S量子点制成的红外探测器,把一个扁平靶心结构等离激元透镜集成到Si O2-Si基质上,这个等     

多层石墨烯纳米带光电探测器理论与性能分析

多层石墨烯具有超宽的光谱吸收范围及独特的光电性能,是制作下一代光电探测器件的理想材料。以石墨烯的带间隧穿理论为基础,提出了一个多层石墨烯纳米带结构的光电探测器模型,纳米带的两端与源极和漏极相连,夹在半导体基质和上下栅极之间。利用这个模型,建立了多层石墨烯纳米带探测器的光电转换机制,讨论了上栅极电压不同时探测器的工作原理,研究了源-漏极间光电流及暗电流与入射光能量的关系,探讨了探测器的偏置电压,耗尽层长度以及带隙取值对暗电流的影响,并分析了不同参数下探测器响应率以及探测率随入射光能量的变化关系。结果表明,探测器的响应率随纳米带层数的增加而增加,受带隙,耗尽层长度和偏置电压的影响,最大的响应率约为103 A·W-1; 通过限制上栅压,带隙等变量可以控制系统暗电流,增大探测器的探测率,最高探测率约为109 cm·Hz1/2·W-1。多层石墨烯纳米带结构可以增强探测器对入射光的吸收,提高探测器的灵敏度以及对弱光的探测能力,实现对太赫兹到远红外波段入射光的有效探测,探测性能远高于许多量子结构和窄带半导体结构的光电探测器。     

强激光辐照下光电探测器响应性能的研究

 响应度R是反映探测器性能的一项重要指标,当探测器被强激光损伤后,光电探测器的响应度将发生改变。设计了一套实时测量探测器响应度的装置,用能量逐渐增加的Nd∶YAG激光辐照PIN光电探测器,获得了探测器响应度与入射强激光功率密度的变化关系。从实验数据可知,探测器被功率密度低于7.6×105W/cm2的激光辐照后不会发生损伤,探测器对532nm参考光的响应度不变;当激光的功率密度超过1.27×106W/cm2时,激光辐照后,探测器对532nm参考光的响应度开始下降,当探测器被功率密度为6.01×106W/cm2的激光辐照后,响应度迅速下降,PN结遭到破坏是探测器响应度下降的根本原因,扫描电镜的结果与我们的分析相一致。     

Bolometric effect in a waveguide-integrated graphene photodetector

Graphene is an alternative material for photodetectors owing to its unique properties.These include its uniform absorption of light from ultraviolet to infrared and its ultrahigh mobility for both electrons and holes.Unfortunately,due to the low absorption of light,the photoresponsivity of graphene-based photodetectors is usually low,only a few milliamps per watt.In this letter,we fabricate a waveguide-integrated graphene photodetector.A photoresponsivity exceeding0.11 A·W ~(-1) is obtained which enables most optoelectronic applications.The dominating mechanism of photoresponse is investigated and is attributed to the photo-induced bolometric effect.Theoretical calculation shows that the bolometric photoresponsivity is 4.6 A·W ~(-1).The absorption coefficient of the device is estimated to be 0.27 dB·μm ~(-1).     

Improvement of sensitivity of graphene photodetector by creating bandgap structure

Graphene has aroused large interest in optoelectronic applications because of its broad band absorption and ultrahigh electron mobility. However, the low absorption of 2.3% seriously limits its photoresponsivity and restricts the relevant applications. In this paper, a method to enhance the sensitivity of graphene photodetector is demonstrated by introducing electron trapping centers and creating a bandgap structure in graphene. The carrier lifetime obviously increases, and more carriers are collected by the electrodes. Compared with intrinsic graphene detector, the defective graphene photodetector possesses high photocurrent and low-driving-voltage, which gives rise to great potential applications in photodetector area.     

A self-powered sensitive ultraviolet photodetector based on epitaxial graphene on silicon carbide

A self-powered graphene-based photodetector with high performance is particularly useful for device miniaturization and to save energy.Here,we report a graphene/silicon carbide(SiC)-based self-powered ultraviolet photodetector that exhibits a current responsivity of 7.4 m A/W with a response frequency of over a megahertz under 325-nm laser irradiation.The built-in photovoltage of the photodetector is about four orders of magnitude higher than previously reported results for similar devices.These favorable properties are ascribed to the ingenious device design using the combined advantages of graphene and SiC,two terminal electrodes,and asymmetric light irradiation on one of the electrodes.Importantly,the photon energy is larger than the band gap of SiC.This self-powered photodetector is compatible with modern semiconductor technology and shows potential for applications in ultraviolet imaging and graphene-based integrated circuits.     

The mechanism of photocurrent enhancement of ZnO ultraviolet photodetector by reduced graphene oxide

An ultraviolet (UV) photodetector based on ZnO-reduced graphene oxide (ZnO-rGO) composites have been successfully fabricated. A pure ZnO photodetector was also fabricated by similar method. In comparison with the pure ZnO UV photodetector, the ZnO-rGO photodetector exhibits a much larger photocurrent and a better light-to-dark-current-ratio. The mechanism of photocurrent enhancement was investigated using I-V characteristics, photoluminescence (PL) spectra, transmittance spectra and time-dependent photocurrent analysis. Results show that the photocurrent enhancement of the ultraviolet photodetector is due to the improvement of the carrier lifetime, because the carrier recombination of ZnO were reduced by rGO. It provides a potential way to fabricate high-response UV photodetectors.     

Dual-wavelength ultraviolet photodetector based on vertical(Al,Ga)N nanowires and graphene

Due to the wide application of UV-A(320 nm–400 nm) and UV-C(200 nm–280 nm) photodetectors, dual-wavelength(UV-A/UV-C) photodetectors are promising for future markets. A dual-wavelength UV photodetector based on vertical(Al,Ga)N nanowires and graphene has been demonstrated successfully, in which graphene is used as a transparent electrode.Both UV-A and UV-C responses can be clearly detected by the device, and the rejection ratio(R254 nm/R450 nm) exceeds35 times at an applied bias of-2 V. The short response time of the device is less than 20 ms. Furthermore, the underlying mechanism of double ultraviolet responses has also been analyzed systematically. The dual-wavelength detections could mainly result from the appropriate ratio of the thicknesses and the enough energy band difference of(Al,Ga)N and Ga N sections.     

高速高饱和单行载流子光探测器的设计与分析

设计了一种In P基的背入射台面结构的单行载流子光探测器.通过在吸收层中采取高斯型掺杂界面及引入合适厚度和掺杂浓度的崖层,使得光探测器同时具备了高速和高饱和电流特性.理论分析表明,在光敏面为14μm2、反向偏压为2 V条件下,该器件的3 d B带宽可达58 GHz,直流饱和电流高达158 m A.在大功率光注入条件下,详细分析了光探测器带宽降低和电流饱和现象,得出能带偏移和电场坍塌是其根本原因的结论.     

Photoconductive multi-layer graphene photodetectors fabricated on etched silicon-on-insulator substrates

Recently, graphene-based photodetectors have been rapidly developed. However, their photoresponsivities are generally low due to the weak optical absorption strength of graphene. In this paper, we fabricate photoconductive multi-layer graphene(MLG) photodetectors on etched silicon-on-insulator substrates. A photoresponsivity exceeding 200 A·W-1is obtained, which enables most optoelectronic application. In addition, according to the analyses of the high photoresponsivity and long photoresponse time, we conclude that the working mechanism of the device is photoconductive effect. The process of photons conversion into conducting electrons is also described in detail. Finally, according to the distinct difference between the photoresponses at 1550 nm and 808 nm, we estimate that the position of the trapping energy is somewhere between 0.4 e V and 0.76 e V, higher than the Fermi energy of MLG. Our work paves a new way for fabricating the graphene photoconductive photodetectors.     

Design and fabrication of multi-channel photodetector array monolithic with arrayed waveguide grating

We have provided optical simulations of the evanescently coupled waveguide photodiodes integrated with a 13-channels AWGs. The photodiode could exhibit high internal efficiency by appropriate choice of layers geometry and refractive index. Aseamless joint structure has been designed and fabricated for integrating the output waveguides of AWGs with the evanescently coupled waveguide photodiode array. The highest simulation quantum efficiency could achieve 92% when the matching layer thickness of the PD is 120 nm and the insertion length is 2 μm. The fabricated PD with 320-nm-thick matching layer and 2-μm-length insertion matching layer present a responsivity of 0.87 A/W.     

Fabrication and performance evaluation of ultraviolet photodetector based on organic /inorganic heterojunction

Organic/inorganic ultraviolet photodetector was fabricated using thermal evaporation technique. Organic/inorganic heterojunction based on thermally evaporated copper (II) acetylacetonate thin film of thickness 200 nm deposited on an n-type silicon substrate is introduced. I–V characteristics of the fabricated heterojunction were investigated under UV illumination of intensity 65 mW/cm². The diode parameters such as ideality factor, n, barrier height, Φ_B, and reverse saturation current, I_s, were determined using thermionic emission theory. The series resistance of the fabricated diode was determined using modified Nord's method. The estimated values of series resistance and barrier height of the diode were about 0.33 KΩ and 0.72 eV, respectively. The fabricated photodetector exhibited a responsivity and specific detectivity about 9 mA/W and 4.6 × 10⁹ Jones, respectively. The response behavior of the fabricated photodetector was analyzed through ON-OFF switching behavior. The estimated values of rise and fall time of the present architecture under UV illumination were about 199 ms and 154 ms, respectively. Finally, enhancing the photoresponsivity of the fabricated photodetector, post-deposition plasma treatment process was employed. A remarkable modification of the device performance was noticed as a result of plasma treatment. These modifications are representative in a decrease of series resistance and an increase of photoresponsivity and specific detectivity. The process of plasma treatment achieved an increment of external quantum efficiency from 5.53% to 8.34% at −3.5 V under UV illumination.