高性能背照式GaN/AlGaN p-i-n紫外探测器的制备与性能

研究了GaN/AlGaN异质结背照式p-i-n结构可见盲紫外探测器的制备与性能。GaN/AlGaN外延材料采用金属有机化学气相沉积（MOCVD）方法生长，衬底为双面抛光的蓝宝石，缓冲层为AlN，n型层采用厚度为0.8 μm的Si掺杂Al0.3Ga0.7N形成窗口层，i型层为0.18 μm的非故意掺杂的GaN，p型层为0.15 μm的Mg掺杂GaN。采用Cl2、Ar和BCl3感应耦合等离子体刻蚀定义台面，光敏面面积为1.96×10-3 cm2。可见盲紫外探测器展示了窄的紫外响应波段，响应区域为310~365 nm，在360 nm处响应率最大，为0.21 A/W，在考虑表面反射时，内量子效率达到82％；优质因子R0A为2.00×108 Ω·cm2，对应的探测率D*=2.31×1013 cm·Hz1/2·W-1；且零偏压下的暗电流为5.20×10-13 A。     

背照式GaN/AlGaN p-i-n紫外探测器的制备与性能

文章研究了p-GaN/i-GaN/n-A l0.3Ga0.7N异质结背照式p-i-n可见盲紫外探测器的制备与性能。器件的响应区域为310~365nm,最大响应率为0.046A/W,对应的内量子效率为19%,优值因子R0A达到1.77×108Ω.cm2,相应的在363nm处的探测率D*=2.6×1012cmHz1/2W-1。     

283 nm背照射p-i-n型AlGaN日盲紫外探测器

实验中使用在蓝宝石衬底上用低压金属有机化学气相沉积（MOCVD）生长的AlGaN基p-i-n结构材料,通过对工艺流程的优化设计,制作了背照射p-i-n型AlGaN日盲紫外探测器,获得了较高的外量子效率。材料中p区和i区的Al组分为40%,n区Al组分为65%。探测器为直径500 m的圆形,光谱响应起止波长为260~310 nm,峰值响应波长283 nm。零偏压下,暗电流密度为2.710-10 Acm-2,对应的R0A参数为3.8108 cm2,峰值响应率为13 mA/W,对应的峰值探测率为1.971012 cmHz1/2W-1。其在-7 V偏压下,峰值响应率达到148 mA/W,对应的外量子效率达到63%。     

AlGaN/PZT探测器的研制及其性能

本文报道了一种新型紫外红外应用的探测器的设计、制备及其性能。探测器由蓝宝石衬底上生长的p-GaN/i-GaN/n-Al0.3Ga0.7N/SiO2/LaNiO3/PZT/Pt多层结构组成。分别测量了紫外和红外的性能。紫外部分,光谱响应范围在302-363nm波段;在波长355nm,探测器零偏响应率为0.064A/W;I-V测量表明零偏暗电流为-1.57×10-12A;该探测器的探测率为1.81×1011cmHz1/2W-1。红外部分,在波长4μm处,探测器响应率为1.58×105cmHz1/2W-1。     

InGaN紫外探测器的制备与性能研究

介绍了InGaN紫外探测器的研制过程,并给出了器件的性能。利用金属有机化学气相沉积(MOCVD)方法生长GaN外延材料,通过刻蚀、钝化、欧姆接触电极等工艺,制作了正照射单元In0.09Ga0.91N紫外探测芯片。并对该芯片进行了I-V特性、响应光谱等测试,得到芯片的暗电流Id为1.00×10-12 A,零偏压电阻R0为1.20×109Ω。该紫外探测器在360~390nm范围内有较高的响应度,峰值响应率在378nm波长处达到0.15A/W,在考虑表面反射时,内量子效率达到60%;优质因子R0A为3.4×106Ω·cm2,对应的探测率D*=2.18×1012 cm·Hz1/2·W-1。     

高性能背照式GaN/AlGaN p-i-n紫外探测器的制备与性能

研究了GaN/AlGaN异质结背照式P-i-n结构可见盲紫外探测器的制备与性能.GaN/MGaN外延材料采用金属有机化学气相沉积(MOCVD)方法生长,衬底为双面抛光的蓝宝石,缓冲层为AiN,n型层采用厚度为0.8 μm的Si掺杂Al0.3Ga0.7形成窗口层,i型层为0.18 μm的非故意掺杂的GaN,P型层为0.15 μm的Mg掺杂GaN.采用C12、Ar和BCl3感应耦合等离子体刻蚀定义台面,光敏面面积为1.96×10-3cm2.可见盲紫外探测器展示了窄的紫外响应波段,响应区域为310-365 nm,在360 nm处响应率最大,为0.21 A/W,在考虑表面反射时,内量子效率达到82%;优质因子R0A为2.00×108 Ω·cm2,对应的探测率D*=2.31×1013·Hz1/2·W-1;且零偏压下的暗电流为5.20×10-13A.     

高量子效率前照式GaN基p-i-n结构紫外探测器

研究了Al0.1Ga0.9N/GaN异质结p-i-n结构可见盲紫外探测器的制备与性能.p区采用Al组分含量为0.1的AlGaN外延材料形成窗口层,使340～365nm波段的紫外光可以直接透过p区到达i区并被吸收,有效提高了这个波段的响应率与量子效率.并且研究了不同p区AlGaN外延层厚度对探测器性能的影响,制备了两种不同p区厚度(0.1μm和0.15μm)的器件,测试结果表明,p区的厚度对200～340nm波段光吸收的量子效率影响较大,而i区的晶体质量的提高可以有效提高340～365nm波段光吸收的量子效率.并且当p区AlGaN厚度为0.15μm时,器件的峰值响应率达到0.214A/W,在考虑表面反射时外量子效率高达85.6%,接近理论极限,并且在零偏压时暗电流密度为3.16nA/cm2,表明器件具有非常高的信噪比.     

高量子效率前照式GaN基p-i-n结构紫外探测器

研究了Al0.1Ga0.9N/GaN异质结p-i-n结构可见盲紫外探测器的制备与性能.p区采用Al组分含量为0.1的AlGaN外延材料形成窗口层,使340～365nm波段的紫外光可以直接透过p区到达i区并被吸收,有效提高了这个波段的响应率与量子效率.并且研究了不同p区AlGaN外延层厚度对探测器性能的影响,制备了两种不同p区厚度(0.1μm和0.15μm)的器件,测试结果表明,p区的厚度对200～340nm波段光吸收的量子效率影响较大,而i区的晶体质量的提高可以有效提高340～365nm波段光吸收的量子效率.并且当p区AlGaN厚度为0.15μm时,器件的峰值响应率达到0.214A/W,在考虑表面反射时外量子效率高达85.6%,接近理论极限,并且在零偏压时暗电流密度为3.16nA/cm2,表明器件具有非常高的信噪比.     

背入射Al0.42Ga0.58N/Al0.40Ga0.60N 异质结 p-i-n 太阳光盲紫外探测器成

在蓝宝石上用MOCVD生长的材料制备了背入射Al0.42Ga0.58N/Al0.40Ga0.60N 异质结 p-i-n 太阳光盲紫外探测器. 从器件的正向I-V特性曲线计算了理想因子n与串联电阻RS分别为3和93Ω. 器件在零偏压下275nm峰值波长处的外量子效率与探测率分别为9%和4.98e11cm·Hz1/2/W,分析表明Al0.42Ga0.58N窗口层在275nm波长处的透过率仅为15.7%,是器件外量子效率和探测率偏低的原因之一.     

长波双色Al_xGa_(1-x)As/GaAs量子阱红外探测器的研制

介绍了长波双色AlxGa1-xAs/GaAs多量子阱红外探测器单元的设计、制作和测试。器件光敏面面积为300μm×300μm,光吸收峰值波长分别为10.8、11.6μm;采用垂直入射光耦合的工作模式,65K温度2V偏压下,两个多量子阱区的暗电流分别为4.23×10-6、4.19×10-6A;黑体探测率分别为1.5×109、6.7×109cm.Hz1/2/W;响应率分别为0.063、0.282A/W。GaAs基量子阱红外探测器(QWIP)材料生长和加工工艺成熟、大面积均匀性好、成本低、不同波段之间的光学串音小,使得AlGaAs/GaAsQWIP在制作多色大面阵方面具有明显的优势。     

p-GaN-i-GaN/AlGaN multiple-quantum well n-AlGaN back-illuminated ultraviolet detectors

The spectral response of back-surface-illuminated p-GaN-i-GaN/AlGaN multiplequantum well (MQW)-n-AlGaN ultraviolet (UV) photodetector is reported. The structure was grown by molecular-beam epitaxy on a c-plane sapphire substrate. A MQW is introduced into the active region of the device to enhance the quantum efficiency caused by the high absorption coefficient of the two-dimensional (2-D) system. Another advantage of using MQW in the active region is the ability to tune the cutoff wavelength of the photodetector by adjusting the well width, well composition, and barrier height. The zero-bias peak responsivity was found to be 0.095 A/W at 330 nm, which corresponds to 36% quantum efficiency from as-grown p-i-n GaN/AlGaN MQW devices. An anomalous effect, occurring in responsivity as a negative photoresponse in the spectra peaked at 362 nm because of poor ohmic contact to p-type GaN, was also observed. Etching the sample in KOH for 30 sec before fabrication removed the surface contaminants and improved the surface smoothness of the as-grown sample, resulting in significant improvement in the device performance, giving a peak responsivity of 0.12 A/W. The device has a quantum efficiency of 45% at 330 nm without the anomalous negative photocurrent.     

246nm p-i-n型背照AlGaN太阳盲紫外探测器的研制

设计并制备出短波长p-i-n型背照AlGaN太阳盲紫外探测器,响应波段为225～255 nm,峰值波长为246nm.材料为在蓝宝石衬底上生长的背照式p-i-n型异质结结构,n型窗口层的AlxGa1-xN中的Al组分为71%,非故意掺杂吸收层中的Al组分为52%.零偏压下测得的暗电流为27 pA,光电流为2.7nA,峰值...     

高温AlN为模板的AlGaN基p-i-n背照式日光盲探测器

第一次报道了以高温AlN为模板层的AlGaN基p-i-n背照式日光盲探测器的制作和器件特性.利用MOCVD方法在(0001)面的蓝宝石衬底上生长了探测器的AlxGa1-xN多层外延材料.在无需核化层的高温AlN模板上生长了p-i-n背照式日光盲探测器的无裂纹高Al组分(0.7)AlGaN多层外延结构.利用在线反射监测仪、三轴X射线衍射及原子力显微镜表征了外延材料的晶体质量.在1.8V的反向偏压下,制作的探测器表现出了日光盲响应特性,在270nm处最大响应度为0.0864A/W.具有约3.5V的正向开启电压,大于20V的反向击穿电压,在2V的反向偏压下暗电流小于20pA.     

高温AlN为模板的AlGaN基p-i-n背照式日光盲探测器

第一次报道了以高温AlN为模板层的AlGaN基p-i-n背照式日光盲探测器的制作和器件特性.利用MOCVD方法在(0001)面的蓝宝石衬底上生长了探测器的AlxGa1-xN多层外延材料.在无需核化层的高温AlN模板上生长了p-i-n背照式日光盲探测器的无裂纹高Al组分(0.7)AlGaN多层外延结构.利用在线反射监测仪、三轴X射线衍射及原子力显微镜表征了外延材料的晶体质量.在1.8V的反向偏压下,制作的探测器表现出了日光盲响应特性,在270nm处最大响应度为0.0864A/W.具有约3.5V的正向开启电压,大于20V的反向击穿电压,在2V的反向偏压下暗电流小于20pA.     

32×32 ultraviolet Al0.1Ga0.9N/GaN p-i-nphotodetector array

We report the fabrication and performance of a 32×32 Al_0.1Ga_0.9N-GaN ultraviolet p-i-n photodetector array. The devices exhibit very low dark current, the mean dark current density is ~4 nA/cm² at 5-V reverse bias, and the dark current distribution is very uniform (~98% of the devices exhibit dark current density <90 nA/cm²). Owing to the design of the p-Al_0.13Ga_0.87N window layer, the external quantum efficiency is as high as 72% at 357 nm. The photocurrent distribution is also presented. The detectivity is estimated to be as high as 8×10 ¹⁴ cm·Hz^1/2·W^-1     

p-GaN/Al0.35Ga0.65N/GaN应变量子阱肖特基紫外探测器

报道了p-GaN/Al0.35Ga0.65N/GaN应变量子阱结构的肖特基紫外探测器的制备及性能.器件的测试结果表明,在p-GaN/Al0.35Ga0.65N/GaN双异质结中强烈的压电极化和Stark效应共同作用下使得器件在正偏和反偏时的响应光谱都向短波方向移动了10nm.零偏下器件在280nm时的峰值响应为0.022A/W,在反向偏压为1V时,峰值响应增加到0.19A/W,接近理论值.在正向偏压下器件则呈平带状态,并在283和355nm处分别出现了两个小峰.在考虑极化的情况下,通过器件中载流子浓度分布的变化解释了器件在不同偏压下的响应特性,发现p-GaN/Al0.35Ga0.65N/GaN中的极化效应对器件的响应特性影响很大,通过改变偏压和适当的优化设计可以使探测器在紫外波段进行选择性吸收.     

A circuit approach to SAW filterbanks for frequency synthesis

A SAW filterbank (2.5 × 0.9 cm) coupled to a miniature silicon-on-sapphire (SOS) p-i-n diode, multiple-input single-output RF switch array (2.5 × 0.25 cm) forms the basis of a very compact UHF frequency synthesizer. In this paper the operation, design, fabrication, and performance of rapid-switching SAW frequency synthesizers is described. Experimental measurements depicting the spectral purity of the waveforms synthesized by two devices; one fabricated on LiTaO3and the other on AlN-on-sapphire, operating over respective frequency ranges of 520-650 MHz and 970-1210 MHz are provided.     

Interdigitated Ge p-i-n photodetectors fabricated on a Si substrate using graded SiGe buffer layers

We report an interdigitated p-i-n photodetector fabricated on a 1-/spl mu/m-thick Ge epitaxial layer grown on a Si substrate using a 10-/spl mu/m-thick graded SiGe buffer layer. A growth rate of 45 /spl Aring//s/spl sim/60 /spl Aring//s was achieved using low-energy plasma enhanced chemical vapor deposition. The Ge epitaxial layer had a threading dislocation density of 10/sup 5/ cm/sup -2/ and a rms surface roughness of 3.28 nm. The 3-dB bandwidth and the external quantum efficiency were measured on a photodetector having 1-/spl mu/m finger width and 2-/spl mu/m spacing with a 25/spl times/28 /spl mu/m/sup 2/ active area. At a wavelength of 1.3 /spl mu/m, the bandwidth was 2.2, 3.5, and 3.8 GHz at bias voltages of -1, -3, and -5 V, respectively. The dark current was 3.2 and 5.0 /spl mu/A at -3 and -5 V, respectively. This photodetector exhibited an external quantum efficiency of 49% at a wavelength of 1.3 /spl mu/m.     

Analysis of external quantum efficiencies of GaN homojunction p-i-nultraviolet photodetectors

We have fabricated and characterized a series of homojunction p-i-n ultraviolet (UV) photodetectors on GaN grown by metalorganic chemical vapor deposition (MOCVD). They exhibit record low dark current densities (~2 nA/cm² at -10-V bias) and high external quantum efficiencies (~45% at λ=362 nm). We have analyzed the spectral external quantum efficiency of these photodiodes using a standard drift-diffusion model and studied its bias dependence. We have found that an optical “dead space” exists underneath the top surface of the p-GaN layer, which may be attributed to the internal electrical field at the p-GaN surface. The presence of this region prevents a meaningful extraction of the electron diffusion length from the quantum efficiency data