半导体量子器件物理讲座 第六讲 半导体量子阱激光器

量子阱结构是半导体光电子器件的核心组成部分,它是半导体光电子集成的重要基础,文章在描述了量子结构的态密度,量子尺寸效应,粒子数反转的基础上,介绍了量子阱导质结构激光器的工作原理,器件结构,器件性能,并对其在可见光激光器和大功率激光器件中显现出来的优越性作了进一步的说明。     

金刚石紫外发光器件研究进展

蓝光或紫外激光在光电子学和光储存方面有广阔的应用，一直是国际上关注的前沿领域．而金刚石是最好的半导体紫外发光材料．特别是用于高温、高压、高功率、强辐射和强腐蚀环境中更能显示其优越性．目前人们已在实验上用同质外延、异质外延的方法制备了金刚石紫外发光二极管，观察到了较强的紫外光发射．人们尝试用金刚石与其他半导体材料结合的方法，成功地研制出了金刚石紫外发光二极管，开拓了该研究领域最新研究方向．文章对这些金刚石紫外发光器件研究的最新进展进行了评述．     

Watt-level continuous-wave and passively Q-switched red lasers pumped by a single blue laser diode

Praseodymium-ion-doped gain materials have the superiority of lasing at various visible wavelengths directly.Simple and compact visible lasers are booming with the development of blue laser diodes in recent years. In this Letter, we demonstrate the watt-level red laser with a single blue laser diode and Pr:YLiF_4 crystal. On this basis,the passively Q-switched pulse lasers are obtained with monolayer graphene and Co:ZnO thin film as the Q-switchers in the visible range.     

Imaging of 1-nm-thick films with 193-nm microscopy

We have implemented a reflected-light microscope operating in the deep ultraviolet at 193 nm. Many materials absorb strongly at this wavelength, providing greatly enhanced contrast compared with visible and near-ultraviolet microscopes. Polymer films as thin as 1 nm and SiO(2) films as thin as 3 nm have been imaged with this nonoptimized instrument. We have also calculated image contrast for several thin-film materials that are important in semiconductor processing, and we show that 193-nm light provides 60-485x better contrast than visible light (500 nm) and 4-95x better contrast than near-ultraviolet light (315 nm) for these materials.     

The effect of temperature on the recombination rate of AlGaN/GaN light emitting diodes

Nitride semiconductors and their alloys recently have versatile applications as high-power and high-efficiency electro optical devices duo to their high thermal stability, direct transition and wide bang-gap. Nanostructure light emitting diodes of these materials have an emission spectrum from infrared to ultraviolet. In this paper, besides simulating a nanostructure nitride semiconductor LED, such as multi quantum well nitride LEDs, the effect of temperature on the recombination rate has been investigated.     

氧化物薄膜晶体管研究进展

氧化物半导体材料因其载流子迁移率高、制备温度低、电学均匀性好、对可见光透明和成本低等优势,被认为是最适合驱动有机发光二极管的薄膜晶体管(TFT)的半导体有源材料之一.目前氧化物TFT已成功地应用在平板显示的驱动背板上.本文从氧化物TFT的历史和发展状况出发,先介绍了氧化物半导体材料及其载流子输运机理,然后详细介绍了氧化物TFT的结构、制备方法以及电学稳定性,接着介绍了近些年来氧化     

Secondary emission of globular photonic crystals based on the opal-POPOP composite

The spectra of secondary emission of a globular photonic crystal such as the opal matrix filled with the POPOP aromatic compound (a known luminophore) and initial materials excited by semiconductor light-emitting diodes were studied. It was found that the luminescence spectrum of opal filled with POPOP significantly differs from luminescence spectra of POPOP itself and initial opal. It was shown that the observed luminescence in the visible region is mostly caused by three-photon parametric light scattering. In this case, the spectral shape is controlled by the photon density of states, differing from the photon density of states of pure opal. The shape of the secondary emission spectrum of artificial opal filled with POPOP was calculated. The effect of the photonic bandgap position on the intensity distribution of spontaneous emission of used luminophore was established.     

氮化镓基发光二极管产业化中的材料物理问题

第三代半导体氮化镓化合物半导体已成为蓝光发光二极管的主流材料，国际上的产业化已成规模，国内也有多家处于中试阶段，由于氮化镓基材料中有如此多的问题没有解决，材料制备设备，器件工艺也极需改进及优化，这既给了中国科研人员及工程技术人员一个机遇，也使他们面临着严峻的挑战。     

Characterization of Schottky barrier diodes fabricated from electrochemical oxidation of α phase brass

By careful selection of chloride ion concentration in aqueous sodium chloride, electrochemical oxidation of α phase brass is shown to permit fabrication of either p-type copper (I) oxide/metal or n-type zinc oxide/metal Schottky barrier diodes. X-ray photoelectron and Auger electron spectroscopies provide evidence that barrier formation and rectifying qualities depend on the relative surface abundance of copper (I) oxide and zinc oxide. X-ray diffraction of the resulting diodes shows polycrystalline oxides embedded in amorphous oxidation products that have a lower relative abundance than the diode forming oxide. Conventional I/V characteristics of these diodes show good rectifying qualities. When neither of the oxides dominate, the semiconductor/metal junction displays an absence of rectification.     

Secondary radiation of synthetic opals loaded by the sodium nitrite ferroelectric

This paper reports on a comparison of transmission, reflection, and secondary radiation spectra of unloaded synthetic opals and samples filled with the sodium nitrite ferroelectric (NaNO₂). The radiation is provided by semiconductor light-emitting diodes operating in the ultraviolet and visible spectral regions. Selective excitation of slow electromagnetic waves in a photonic crystal, an effect observed when the exciting radiation frequency approaches the stop-band edge, is studied.     

ZnO可见区发光机理研究进展

近年来,科研工作者对ZnO纳米材料研究产生了浓厚的兴趣。ZnO是一种具有宽带隙(3.37 eV)和较大的激子束缚能(60 meV)的六方纤锌矿结构半导体材料。它具有优异的光电、压电、压敏及发光等特性,在发光(激光)二极管、传感器、发光器件、紫外探测器等领域都有非常好的应用前景。至今,有很多非常成熟的实验方法(包括静电纺丝、水热法、溶胶-水热法、化学气相沉积法、旋涂法及电化学沉积法等)用来合成ZnO纳米材料,如纳米线、纳米棒、纳米盘及量子点等。氧化锌纳米结构的制备和性质已得到了广泛的研究,ZnO的可见发光机理一直是研究的热点,但很少有人对可见光范围内的光致发光进行总结。光致发光光谱能反映一些重要信息,如表面缺陷和氧空位、半导体材料的表面状态、光诱导电荷转移过程等。有学者认为ZnO的发光机理与其晶体缺陷有关,还有研究者认为其发光机理与氧空位有关等。通过量子限域效应、带边调制、表面修饰方法、缺陷调控方法等方面综述了ZnO可见区发光机理。     

半导体照明发光二极管(LED)芯片制造技术及相关物理问题

以化合物半导体材料为发光元件的半导体固态照明正引发人类照明史上的又一次伟大革命.目前,局限半导体照明广泛应用的主要技术瓶颈有：出光效率（或外量子效率）,单管最大可发光通量（或最大可工作功率）,单位光通量的成本和发光二极管可正常使用寿命.文章综述和分析了与芯片发光效率（或外量子效率）和单芯最大可发光通量（或最大可工作功率）相关的制造技术和相关物理问题.     

Response of metal-insulator-metal point contact diodes to visible laser light

Video response and mixing behaviour of metal-insulator-metal point contact diodes have been investigated for visible laser light. Thermally enhanced tunneling is shown to dominate the dc detection behavior of those diodes, while mixing of frequencies being more than several MHz apart is a more complex phenomenon involving thermal, field-and photo-assisted tunneling. In further experiments the potential of point contact diodes for optical heterodyne spectroscopy was examined. Two green laser lines of 122 GHz frequency difference were mixed with the second harmonic of an appropriate microwave frequency, generated simultaneously on the diode. The modestS/N ratio achieved has to be assigned to the different behaviour of metal-insulator-metal diodes in the visible and rf range.     

Organic optoelectronic device fabrication using standard UV photolithography

The fabrication of organic optoelectronic devices requires patterning techniques that are compatible with organic semiconductor materials. Photolithography represents, by far, the dominant patterning approach for inorganic electronics and optoelectronics. High speed, parallel patterning capability, high resolution, and the availability of standard equipment make this technology also very attractive for applications in the field of organic semiconductor technology. In the present paper we present a successful implementation of photolithography to fabricate organic diodes. This process provides the basis for a future high‐resolution monolithic integration of organic optoelectronic and photonic devices into one photonic circuit. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Electrical characteristics of the hydrogen pre-annealed Au/n-GaAs Schottky barrier diodes as a function of temperature

We investigated the passivation effects of hydrogen gas on the Au/n-GaAs Schottky barrier diodes in a wide temperature range. Reference diodes were prepared by evaporating barrier metal on semiconductor wafers un-annealed in N₂ gas atmosphere. The other diodes were made by evaporating barrier metal on n-GaAs semiconductor substrates annealed in H₂ atmosphere. Then, electrical measurements of all diodes were carried out by using closed-cycle Helium cryostat by steps of 20 K in the temperature range of 80-300 K in dark. The basic diode parameters such as ideality factor and barrier height were consequently extracted from electrical measurements. It was seen that ideality factors increased and barrier heights decreased with the decreasing temperature. The case was attributed to barrier inhomogeneity at the metal/semiconductor interface. Barrier heights of the diodes made from samples annealed in H₂ gas atmosphere were smaller than those of reference diodes at low temperatures. Here, it was ascribed to the fact that hydrogen atoms passivated dangling bonds on semiconductor surface in accordance with former studies.     

Conducting polymer based biomolecular electronic devices

Biomolecular electronics is rapidly evolving from physics, chemistry, biology, electronics and information technology. Organic materials such as proteins, pigments and conducting polymers have been considered as alternatives for carrying out the functions that are presently being performed by semiconductor silicon. Conducting polymers such as polypyrroles, polythiophenes and polyanilines have been projected for applications for a wide range of biomolecular electronic devices such as optical, electronic, drug-delivery, memory and biosensing devices. Our group has been actively working towards the application of conducting polymers to Schottky diodes, metal-insulator-semiconductor (MIS) devices and biosensors for the past 10 years. This paper is a review of some of the results obtained at our laboratory in the area of conducting polymer biomolecular electronics.     

Projected noise in submillimeter-wave mixers with InSb Schottky diodes

The reduction of the equivalent noise temperature in liquidnitrogen-cooled submillimeter-wave mixers by the use of Schottky barriers on InSb instead of GaAs is evaluated by an analytical model that assumes limited local oscillator power and matched impedances. The calculations, executed at 1.0 and 1.8 Thz, take plasma resonance and skin effect into account. For single and multiple contacts on homogeneous semiconductor materials of optimum doping, the noise of InSb diodes is smaller than that of GaAs diodes by a factor of 3 to 14. A simplified model is used to predict the performance of epitaxial structures as well as alternative materials.This paper presents the results of one phase of research performed at the Jet Propulsion Laboratory, California Institute of Technology, sponsored by the National Aeronautics & Space Administration under Contract NAS 7-100.     

Confocal optical beam induced current microscopy of light-emitting diodes with a white-light supercontinuum source

To improve the efficiency of confocal optical beam induced current (OBIC) and the non-destructive, high-resolution analysis of semiconductor media we report the application of a white-light supercontinuum laser source capable of confocal OBIC across a wide spectral range. To demonstrate the capability of this source, we performed confocal OBIC of light emitting diodes with varying absorption and emission properties in the visible spectrum. Using the wavelength flexibility afforded by the broadband laser source, we were able to determine and apply the optimum excitation wavelength range for efficient confocal OBIC instead of applying inferior fixed wavelength laser sources. PACS 87.64.Tt; 85.30.De     

Transition metal dichalcogenides (TMDCs) heterostructures: Optoelectric properties

Transition metal dichalcogenides (TMDCs) have suitable and adjustable band gaps, high carrier mobility and yield. Layered TMDCs have attracted great attention due to the structure diversity, stable existence in normal temperature environment and the band gap corresponding to wavelength between infrared and visible region. The ultra-thin, flat, almost defect-free surface, excellent mechanical flexibility and chemical stability provide convenient conditions for the construction of different types of TMDCs heterojunctions. The optoelectric properties of heterojunctions based on TMDCs materials are summarized in this review. Special electronic band structures of TMDCs heterojunctions lead to excellent optoelectric properties. The emitter, p-n diodes, photodetectors and photosensitive devices based on TMDCs heterojunction materials show excellent performance. These devices provide a prototype for the design and development of future high-performance optoelectric devices.     

稀土离子掺杂钙钛矿纳米晶的光学性质和应用

近年来,钙钛矿纳米晶由于具有优异的光电性质,在发光、光电转换等领域获得了广泛的研究,已然成为科研界的"明星材料".然而,钙钛矿纳米晶存在一些不足之处(例如稳定性差、光谱仅限于可见光区等),限制了其应用.稀土离子具有丰富的4f能级和特殊的电子构型,因此,将稀土离子掺杂到钙钛矿纳米晶中,能够显著提升材料的光电性质,并改善稳...