生长在p-GaAs衬底上的ZnO基异质结二极管电致发光

利用等离子体辅助分子束外延在p型砷化镓衬底上制备了ZnO异质结发光二极管。实验表明:GaAs与ZnO之间的氧化镁绝缘层能够有效改善器件光电性能,I-V特性的研究表明该器件具有良好的整流特性,开启电压为3 V,电致发光光谱由一个紫外发光峰和一个可见发光带构成,其来源分别为ZnO层中近带边缺陷以及深能级缺陷相关的辐射复合。     

Electroluminescence of an n-ZnO/p-GaN Heterojunction under Forward and Reverse Biases

Electroluminescent characteristics of n-ZnO/p-GaN heterojunctions under forward and reverse biases are studied. Emissions at 389nm and 57Ohm are observed under forward bias. An unusual emission at 390ram appears under reverse bias, and is attributed to the recombination in the p-GaN side of the heterojunction. The yellow emission peaked at 57Ohm is suppressed under reverse bias. The light intensity exponentially depends on the reverse current. The emission under reverse bias is correlated to tunnelling carrier transport in the heterostructure. Our results also support that the well-known yellow band of GaN comes from the transitions between some near-conduction-band-edge states and deep localized acceptor states.     

用电化学沉积法制备ZnO/Cu2O异质p-n结

由于P型ZnO的制备仍然存在一定的困难,限制了ZnO在光电方面的应用,尤其是在发光二极管和激光器的实际应用,目前利用P型的透明半导体氧化物与n型ZnO制备异质p-n结,成为新的研究热点。选择P型导电Cu2O与ZnO制备出异质p-n结。Cu2O是一种典型的P型半导体材料,禁带宽度为2．1eV,可见光范围的吸收系数较高。首次利用电化学沉积的方法制备了ZnO／Cu2O异质p-n结,研究了电沉积ZnO,Cu2O的生长机制和ZnO／Cu2O异质结的结构、光学和电学特性。     

氧化锌/金刚石薄膜异质结紫外光探测器

采用射频磁控溅射法在p型自支撑金刚石衬底上制备了高度c轴取向的n型氧化锌薄膜.研究了不同的溅射功率对氧化锌薄膜质量的影响.通过半导体特性分析系统测试了氧化锌/金刚石异质结的电流-电压特性,结果显示该异质结二极管具有良好的整流特性,开启电压约为1.6 V.在此基础上制备了结型紫外光探测器,并对其光电性能进行了研究.结果表...     

异质结线性吸收谱中的等离激元效应

将染料分子与半导体表面所组成的异质结与金属纳米粒子的耦合系统作为研究对象,考虑分子的振动态,在偶极-偶极近似下研究其线性吸收谱及相关的电荷转移动力学过程. 对金属纳米粒子作用下吸收谱变宽及相关的电子转移增强过程作了仔细的分析和讨论,理论分析了金属钠米粒子的表面等离激元对异质结中超快电子转移的影响. 关键词： 金属纳米粒子 等离激元 异质结电荷转移     

分子束外延生长Si/GaP(III)异质结的界面特性

关键词：     

高效率PBRS InGaAsP/InP LED的研究

用于单模光纤系统的平面隐埋脊型(PBRS)InGaAs P/IuP DH LED已研制成功.本文对材料和器件设计作了简要描述.异质结晶体系采用二次液相外延生长,器件具有斜胶面受激抑制结构和平面隐埋脊型有源区,用激光焊接金属化封装技术使器件与单模光纤耦合对接.波器件在单模光纤中的入纤功率达35μW,是国内已见报道中最高的结果,带宽195MHz.在四次群传输实验中,无中继传输距由大于20公里.     

CVD法制备p-ZnO薄膜/n-Si异质结发光二极管及其性能研究

利用简单的化学气相沉积方法, 首先在n-Si衬底上生长Sb掺杂p-ZnO薄膜, 并在此基础上制作了p-ZnO/n-Si异质结发光二极管．对制备的Sb掺杂ZnO薄膜 在800 ℃下进行了热退火处理, 发现退火后样品的晶体质量和表面形貌都得到明显提高, 并且薄膜呈现的电导类型为p型, 载流子浓度为9.56× 10¹⁷ cm^-3. 此外, 该器件还表现出良好的整流特性, 正向开启电压为4.0 V, 反向击穿电压为9.5 V. 在正向45 mA的注入电流条件下, 器件实现了室温下的电致发光. 这说明较高质量的ZnO薄膜也可以通过简单的化学气相沉积方法来实现, 这为ZnO基光电器件的材料制备提供了一种简单可行的方法. 关键词： CVD p-ZnO 异质结 电致发光     

在蓝宝石衬底上生长的氧化锌p-n同质结发光二极管

用等离子体辅助的分子束外延的方法在蓝宝石衬底上生长了氧化锌的p-n同质结发光二极管。在实验中p型ZnO层是采用NO等离子体作为掺杂剂生长的。在低温下,二极管的I-V特性曲线显示了典型的p-n结整流特性,并且具有很低的开启电压（4V）。在实验中得到了位于蓝紫区的电致发光。     

ZnMgO/n-ZnO/ZnMgO/p-GaN异质结LED的紫外电致发光

利用等离子体辅助分子束外延( P-MBE)技术制备了ZnMgO/n-ZnO/ZnMgO/p-GaN异质结LED.Ni/Au电极与p-GaN、In电极与ZnMgO之间都形成了良好的欧姆接触.在ZnMgO/n-ZnO/ZnMgO/p-GaN异质结器件中观察到了明显的整流特性.异质结的电致发光强度随着注入电流的增大而逐渐增强...     

Low-voltage blue light emission from n-ZnO/p-GaN heterojunction formed by RF magnetron sputtering method

High quality n-ZnO/p-GaN heterojunction was fabricated by growing highly crystalline ZnO epitaxial films on commercial p-type GaN substrates via radio frequency (RF) magnetron sputtering. Low-voltage blue light emitting diode with a turn-on voltage of ∼2.5 V from the n-ZnO/p-GaN heterojunction was demonstrated. The diode gives a bright blue light emission located at ∼460 nm and a low threshold voltage of 2.7 V for emission. Based on the results of the photoluminescence (PL) and electroluminescence (EL) spectra, the origins of the EL emissions were studied in the light of energy band diagrams of ZnO–GaN heterojunction, and may attribute to the radiative recombination of the holes in p-GaN and the electrons injected from n-ZnO, which almost happened on the side of p-GaN layer. These results may have important implications for developing short wavelength optoelectronic devices.     

Improvement in electroluminescence performance of n-ZnO/Ga_2O_3 /p-GaN heterojunction light-emitting diodes

n-ZnO/p-GaN heterojunction light-emitting diodes with and without a Ga2O3 interlayer are fabricated. The electroluminescence （EL） spectrum of the n-ZnO/p-GaN displays a single blue emission at 430 nm originating from GaN, while the n-ZnO/Ga2O3/p-GaN exhibits a broad emission peak from ultraviolet to visible. The broadened EL spectra of n-ZnO/Ga2O3/p-GaN are probably ascribed to the radiative recombination in both the p-GaN and n-ZnO, due to the larger electron barrier （ΔEC=1.85 eV） at n-ZnO/Ga2O3 interface and the much smaller hole barrier （ΔEV=0.20 eV） at Ga2O3/p-GaN interface.     

氧化锌基材料、异质结构及光电器件

Ⅱ-Ⅵ族直接带隙化合物半导体氧化锌（ZnO）的禁带宽度为3.37 eV,室温下激子束缚能高达60 meV,远高于室温热离化能（26 meV）,是制造高效率短波长探测、发光和激光器件的理想材料。历经10年的发展,ZnO基半导体的研究在薄膜生长、杂质调控和器件应用等方面的研究获得了巨大的进展。本文主要介绍了以国家“973”项目（2011CB302000）研究团队为主体,在上述方面所取得的研究进展,同时概述国际相关研究,主要包括衬底级ZnO单晶的生长,ZnO薄膜的同质、异质外延,表面/界面工程,异质结电子输运性质、合金能带工程,p型掺杂薄膜的杂质调控,以及基于上述结果的探测、发光和激光器件等的研究进展。迄今为止,该团队已经实现了薄膜同质外延的二维生长、硅衬底上高质量异质外延、基于MgZnO合金薄膜的日盲紫外探测器、可重复的p型掺杂、可连续工作数十小时的同质结紫外发光管以及模式可控的异质结微纳紫外激光器件等重大成果。本文针对这些研究内容中存在的问题和困难加以剖析并探索新的研究途径,期望能对ZnO材料在未来的实际应用起到一定的促进作用。     

氧化锌基材料、异质结构及光电器件

Ⅱ-Ⅵ族直接带隙化合物半导体氧化锌(ZnO)的禁带宽度为3.37 eV,室温下激子束缚能高达60 meV,远高于室温热离化能(26 meV),是制造高效率短波长探测、发光和激光器件的理想材料。历经10年的发展,ZnO基半导体的研究在薄膜生长、杂质调控和器件应用等方面的研究获得了巨大的进展。本文主要介绍了以国家"973"项目(2011CB302000)研究团队为主体,在上述方面所取得的研究进展,同时概述国际相关研究,主要包括衬底级ZnO单晶的生长,ZnO薄膜的同质、异质外延,表面/界面工程,异质结电子输运性质、合金能带工程,p型掺杂薄膜的杂质调控,以及基于上述结果的探测、发光和激光器件等的研究进展。迄今为止,该团队已经实现了薄膜同质外延的二维生长、硅衬底上高质量异质外延、基于MgZnO合金薄膜的日盲紫外探测器、可重复的p型掺杂、可连续工作数十小时的同质结紫外发光管以及模式可控的异质结微纳紫外激光器件等重大成果。本文针对这些研究内容中存在的问题和困难加以剖析并探索新的研究途径,期望能对ZnO材料在未来的实际应用起到一定的促进作用。     

Influence of growth temperature and post-annealing on an n-ZnO/p-GaN heterojunction diode

We report on an n-ZnO/p-GaN heterojunction diode fabricated from zinc oxide (ZnO) films at various growth temperatures (450, 500, 550, and 600 °C) by RF sputtering. The films were subsequently annealed at 700 °C in N₂ ambient. To investigate the influence of the growth temperature of n-ZnO films, the microstructural, optical, and electrical properties were measured using scanning electron microscopy (SEM), X-ray diffraction (XRD), photoluminescence (PL), and Hall measurements. The XRD pattern showed the preferred orientation along the c-axis (002) regardless of growth temperature. The PL spectra showed a dominant sharp near-band-edge (NBE) emission. Current–voltage (I–V) curves showed excellent rectification behavior. The turn-on voltage of the diode was observed to be 3.2 V for the films produced at 500 °C. The ideality factor of ZnO film was observed to be 1.37, which showed the best performance of the diode.     

Effects of AlN nucleation layer thickness on crystal quality of AlN grown by plasma-assisted molecular beam epitaxy

In this paper,the effects of thickness of AlN nucleation layer grown at high temperature on AlN epi-layer crystalline quality are investigated.Crack-free AlN samples with various nucleation thicknesses are grown on sapphire substrates by plasma-assisted molecular beam epitaxy.The AlN crystalline quality is analysed by transmission electron microscope and x-ray diffraction (XRD) rocking curves in both (002) and (102) planes.The surface profiles of nucleation layer with different thicknesses after in-situ annealing are also analysed by atomic force microscope.A critical nucleation thickness for realising high quality AlN films is found.When the nucleation thickness is above a certain value,the (102) XRD full width at half maximum (FWHM) of AlN bulk increases with nucleation thickness increasing,whereas the (002) XRD FWHM shows an opposite trend.These phenomena can be attributed to the characteristics of nucleation islands and the evolution of crystal grains during AlN main layer growth.