基于氮化镓集成光电子芯片的单通道全双工可见光通信系统

为了应对新一代通信技术频谱危机，根据量子阱二极管发光谱和探测谱存在重叠区的物理现象，提出一种基于氮化镓集成光电子芯片的单通道全双工可见光通信系统。采用具有相同量子阱结构的一对蓝光、绿光氮化镓量子阱二极管器件，分别作为光发射器和光接收器，器件集成Ti O2/Si O2分布式布喇格反射镜（DBR），将入射光和发射光隔离，实现单通道全双工光通信。测试结果表明，该可见光通信系统通过集成氮化镓光电子芯片，节约了信道空间，对面向未来6G的可见光通信技术的发展具有重要意义。     

可见光无线传能通信一体化芯片

为了解决水下环境中物联网感知终端的能源供给难题，利用氮化镓量子阱二极管的多功能光电特性，采用兼容的制造工艺，在同一块氮化镓芯片上集成能源、照明、通信和感知等器件，在器件之间实现互联，制备出氮化镓能源通信感知一体化芯片，并对该芯片进行了可见光无线传能和通信实验。实验结果表明：该芯片能够吸收外界的光脉冲信号并产生稳定的信号输出，且信号发射速率能够达到1 Mb/s，具有中继通信的潜力；在水下环境中该芯片也能实现能源的采集与信号通信。     

表面等离子体提高GaN-LED发光效率的研究进展

表面等离子体能够增强氮化镓发光二极管的发光效率,为高效发光二极管芯片的研究提供了可行的方案。近年来,国内外研究小组在利用表面等离子体增强氮化镓发光二极管发光效率的实验中,取得了很多有价值的结果。介绍了具有金属薄膜、金属颗粒和金属光子晶体等典型结构的氮化镓发光二极管。重点探讨了表面等离子体增强发光二极管发光的机理、结构和关键技术。对具有二维金属光子晶体的氮化镓发光二极管发光增强机理进行了分析和预测,认为利用二维光子晶体可以从内量子效率和外量子效率两方面增强器件发光,并且有很好的可控制性,是提高发光效率的可行方案。     

覆盖S+C波段的宽光谱带宽InGaAlAs/InP量子阱结构

通过理论仿真和实际制备测试,分析比较了基于非对称量子阱结构(10 nm厚和6 nm厚的量子阱组合)的光放大芯片与对称量子阱结构(10 nm厚量子阱)的光放大芯片的性能。两种结构的理论模式增益同最终实测值符合较好。最终光谱测试结果显示,对称量子阱结构的光放大芯片存在基态增益饱和的现象,在大电流注入情况下,激态跃迁占据优势,从而造成光谱宽度急剧下降。而非对称量子阱结构的光放大芯片的光谱宽度随着注入电流的增加不断拓宽,在600 mA下实现199.7 nm光谱带宽,覆盖S+C波段。由此可见,非对称量子阱结构更有利于实现高功率、宽光谱的光放大芯片。     

面向可见光通信的硅基InGaN/GaN多量子阱波导定向耦合器光子集成芯片

利用可见光信号作为新型信息载体的光通信技术近些年来得到长足发展,为了开发新一代光子集成芯片作为可见光通信网络的终端器件,满足可见光信号发射、接收、传输与处理的复合需求,该文基于硅基InGaN/GaN多量子阱材料,设计了一种集成可见光波段微型发光二极管(LED)光源、波导定向耦合器、微型光电探测器于一体的光子集成芯片。该芯片利用InGaN/GaN多量子阱材料的发光探测共存现象,实现了上述复合功能。微型LED光源作为发射端,可以发射出蓝色波段的可见光信号,其发光强度受到注入电流的线性调制,可实现调幅可见光通信,适合作为可见光通信的发射端。微型LED光源发射的可见光信号传输进入波导定向耦合器,实现了片内有效传输耦合和光功率平均分配。经过耦合传输的可见光信号进入微型光电探测器,可以监测到与耦合传输的光信号强度相匹配的光电流。最后,可见光通信测试也表明该芯片可实现有效的可见光通信。该研究为发展面向可见光通信网络需求的复合功能光子集成芯片终端提供了更多可能性。     

980nm垂直腔型面发射和接收器件及列阵的研制

采用相同生长结构的MOCVD外延片,研究制备适用于单片集成的垂直腔面发射与接收器件及列阵,发射及接收波长相同,由谐振腔模式决定.采用双氧化电流限制结构,优化串联电阻,提高电光转换效率,制备980nm波段发光器件及1×16列阵芯片,发射谱线半宽≤4.8nm,注入电流为50mA时,发射功率为0.7mW.对列阵芯片用探针进行在线检测,器件均有良好的发光特性.接收器件光电响应具有良好的波长和空间选择特性,谐振接收波长可利用不同角度光入射实现简单易行的调节.通过腐蚀器件顶部DBR的方法调节入射镜反射率,可以分别实现具有单片集成结构的谐振增强型发射和接收器件的优化设计.     

980nm垂直腔型面发射和接收器件及列阵的研制

采用相同生长结构的MOCVD外延片,研究制备适用于单片集成的垂直腔面发射与接收器件及列阵,发射及接收波长相同,由谐振腔模式决定.采用双氧化电流限制结构,优化串联电阻,提高电光转换效率,制备980nm波段发光器件及1×16列阵芯片,发射谱线半宽≤4.8nm,注入电流为50mA时,发射功率为0.7mW.对列阵芯片用探针进行在线检测,器件均有良好的发光特性.接收器件光电响应具有良好的波长和空间选择特性,谐振接收波长可利用不同角度光入射实现简单易行的调节.通过腐蚀器件顶部DBR的方法调节入射镜反射率,可以分别实现具有单片集成结构的谐振增强型发射和接收器件的优化设计.     

离子注入法制备GaAsl量子阱集成多波长发光芯片

报道了用离子注入方法和组合技术制备的ＡｌＧａＡｓ／ＧａＡｓ单量子阱多波长发光集成芯片,利用量子阱果面混合原理在同一块ＧａＡｓ衬底片上获得了２０多个发光波长从７８７￣７２４ｎｍ的ＧａＡｓ量子阱发光单元,研究了不同剂量的Ａｓ和Ｈ离子分别单独注入和迭加组合注入对量子阱发光峰位的影响,采用了组事技术和离子注入技术大大筒化了制备工艺过程,这种上发光芯片对于波分复用器件和建立离子注入数据库等方面都有重要的意义     

卷曲量子阱红外探测器应力变化及对探测性能的影响

研究了卷曲量子阱红外探测器的应力状态变化及对光电性能的影响,发现拉应力使导带能级上移,压应力则使其下移,且双量子阱结构的卷曲薄膜的能带移动取决于两个量子阱的合应力变化;卷管薄膜可以有效将应力变化转变为应变,从而减小环境温度变化对能带移动的影响,提高红外器件温度稳定性;褶皱薄膜相比于卷管薄膜的量子阱具有较大的压应力,导致其光响应率较低;相同外加偏压下,卷管器件比褶皱器件的电压响应率提高约2.5倍。     

亚微米CMOS结构光学交叉互连电路芯片的设计

同单路光接收／发送电路系统相比,采用单片集成的多路交叉互连接收／发送系统可实现大容量信息交换和高度复杂的信息处理。给出了与１０×１０阵列多量子阱（ＭＱＷ）器件芯片倒扣连接的接收／发送交叉互连电路的设计,芯片电路采用０．３５／０．５μｍ设计规则、三层金属布线ＣＭＯＳ结构,在２ｍｍ×２ｍｍ芯片上,可完成１６路接收／发送及１６×１６信号交叉互连的功能。     

单片集成式氮化镓基发光二极管的设计与制造

We report a new monolithic structure of GaN-based light-emitting diode(LED) which can be operated under high voltage or alternative current. Differing from the conventional single LED chip, the monolithic lightemitting diode(MLED) array contains microchips which are interconnected in series or parallel. The key chip fabrication processing methods of the monolithic LED array include deep dry etching, sidewall insulated protection, and electrode interconnection. A 12 V GaN-based blue high voltage light emitting diode was designed and fabricated in our experiment. The forward current-voltage characteristics of MLEDs were consistent with those of conventional single junction light emitting diodes.     

Fabrication of Large-Area Suspended MEMS Structures Using GaN-on-Si Platform

In this letter, piezosensitive elements featuring large-size suspended gallium nitride (GaN) microstructures are fabricated with a two-step dry-release technique using the GaN-on-Si platform. The suspended microstructures are integrated with highly piezosensitive AlGaN/GaN heterostructures as sensing units to realize the GaN-based integrated microsensors. To characterize the residual-stress distribution of the fabricated microstructures, micro-Raman spectroscopy is employed. A microaccelerometer structure with a 250 times 250-mum² proof-mass area is fabricated with the proposed fabrication technique, and the piezoresponse properties of the integrated sensing elements are characterized through bending experiment.     

High-Speed GaN-Based Green Light-Emitting Diodes With Partially n-Doped Active Layers and Current-Confined Apertures

We demonstrate a high-speed GaN-based green light-emitting diode for plastic optical fiber (POF) communication applications. By using a combination of n-type doping and undoped In_xGa_1-xN/GaN based multiple quantum wells (MQWs), and a 76-mum-diameter current-confined aperture structure, we can obtain an extremely high electrical-to-optical (E-O) 3 dB bandwidth (~330 MHz), which is limited by the spontaneous recombination lifetime of the MQWs. A reasonable coupled power (-264 muW) can be simultaneously achieved for a 2 mm in diameter POF with a 0.5 numerical aperture (NA).     

Nearly White-Light Emission From GaN-Based Light-Emitting Diodes Integrated With a Porous SiO 2 Layer

In this letter, we develop a nearly white-light-emitting device by integrating blue/green emission from a GaN-based light-emitting diode with red emission from a porous SiO₂ layer. The porous SiO ₂ layer was fabricated by a novel process procedure to create Si nanocrystals on top of the n-type GaN layer. Red light is generated from the metal-oxide-semiconductor (Ni-Au-SiO₂ oxide-n-type GaN) structure due to the electron-hole recombination in the Si nanocrystals. The device shows a blue light emission at a low biased voltage and nearly white-light emission (green and red colors) at a bias voltage between 14 and 16 V. Our results show the potential of applying such an integrated structure to white-light illumination     

GaN-based blue laser diode with 6.0 W of output power under continuous-wave operation at room temperature

In this work,we reported the room-temperature continuous-wave operation of 6.0 W GaN-based blue laser diode(LD),and its stimulated emission wavelength is around 442 nm.The GaN-based high power blue LD is grown on a c-plane GaN substrate by metal organic chemical vapor deposition(MOCVD),and the width and length of the ridge waveguide structure are 30 and 1200 μm,respectively.The threshold current is about 400 mA,and corresponding threshold current density is 1.1 kA/cm2.     

GaN基光电子材料及器件的研究

GaN材料是性能优越的化合物半导体,与其相关的合金材料可以制作出高亮度蓝光、绿光发光二极管、紫外探测器、半导体蓝色激光器(LD)等具有重要应用价值的光电子器件,因而备受重视,本文综述了GaN基光电子器件研究开发现状及其应用前景。     

Wafer fusion of infrared laser diodes to GaN light-emittingheterostructures

In this letter, we use wafer fusion to integrate AlGaInAs quantum-well (QW) laser heterostructures to GaN laser diode and light-emitting diode (LED) structures. After fusion of the laser heterostructure to the GaN layers, AlGaInAs QW lasers are fabricated and characterized. Lasers of 15×510 μm operate with a threshold of 20 mA and external differential quantum efficiency of 15.5%/facet at a wavelength of 820 nm, InGaN-GaN LED's, fabricated 75 μm from the lasers, emit at 458 nm. The operation of the lasers and LED's fused to GaN demonstrates that the fused interface is mechanically robust, and the properties of fused heterostructures are not adversely affected by the fusion process     

GaN-based light emitting diodes on nano-hole patterned sapphire substrate prepared by three-beam laser interference lithography

Nano-hole patterned sapphire substrates (NHPSSs) were successfully prepared using a low-cost and high-efficiency approach, which is the laser interference lithography (LIL) combined with reactive ion etching (RIE) and inductively coupled plasma (ICP) techniques. Gallium nitride (GaN)-based light emitting diode (LED) structure was grown on NHPSS by metal organic chemical vapor deposition (MOCVD). Photoluminescence (PL) measurement was conducted to compare the luminescence efficiency of the GaN-based LED structure grown on NHPSS (NHPSS-LED) and that on unpatterned sapphire substrates (UPSS-LED). Electroluminescence (EL) measurement shows that the output power of NHPSS-LED is 2.3 times as high as that of UPSS-LED with an injection current of 150 mA. Both PL and EL results imply that NHPSS has an advantage in improving the crystalline quality of GaN epilayer and light extraction efficiency of LEDs at the same time.     

Enhanced Luminance Efficiency of Wafer-Bonded InGaN–GaN LEDs With Double-Side Textured Surfaces and Omnidirectional Reflectors

A p-side-up GaN-based light-emitting diode (LED) on a silicon substrate was designed and fabricated using a combination of omnidirectional reflector (ODR) and double-side textured surface (both p-GaN and undoped-GaN) structures via surface-roughening, laser lift-off (LLO) and wafer-bonding technologies. The reflectivity of the designed ODR can reach 99.1% at a wavelength of 460 nm. The textured surface of top p-GaN was achieved under low temperature (LT) conditions using metalorganic chemical vapor deposition. It was found that the GaN LED with an extra 200-nm-thick LT p-GaN layer exhibits a 50% enhancement in luminance intensity. The luminance efficiency of double-side roughened silicon–ODR–GaN LED with a small chip size of 250 $mu {hbox {m}} times {hbox {500}}~mu$m can be improved from 23.2% to 28.2% at an injection current of 20 mA. For the case of 1 mm $times$ 1 mm in chip size, the saturation behavior of the light output power is not observed when an injection current increased from 20 to 350 mA, where the luminance efficiency at 20 mA can reach 28.9%, demonstrating an enhancement by 46%, as compared with that of the conventional GaN–sapphire LEDs. These enhanced results can be attributed to higher reflectivity from the ODR and multiple chances of light emitted from the active region to escape, as well as a centralizing effect of light along the vertical direction.      

Enhanced light output in nitride-based light-emitting diodes by roughening the mesa sidewall

In this letter, we will report on a nitride-based light emitting diode with a mesa sidewall roughening process that increases light output power. The fabricated GaN-based light-emitting diode (LED) wafers were first treated through a photoelectrochemical (PEC) process. The Ga/sub 2/O/sub 3/ layers then formed around the GaN : Si n-type mesa sidewalls and the bottoms mesa etching regions. Selective wet oxidation occurred at the mesa sidewall between the p- and the n-type GaN interface. The light output power of the PEC treated LED was seen to increase by about 82% which was caused by a reduced index reflectance of GaN-Ga/sub 2/O/sub 3/-air layers, by a rough Ga/sub 2/O/sub 3/ surface, by a microroughening of the GaN sidewall surface, and by a selective oxidation step profile of the mesa sidewall that increases the light-extraction efficiency from the mesa sidewall direction. Consequently, this wet PEC treated process is suitable for high powered nitride-based LEDs lighting applications.