State-of-the-art multijunction cell designs have the potential for significant improvement before going to higher number of junctions. For example, the Voc can be substantially increased if the photon recycling taking place in the junctions is enhanced. This has already been demonstrated (by Alta Devices) for a GaAs single-junction cell. For this, the loss of re-emitted photons by absorption in the underlying layers or substrate must be minimized. Selective back surface reflectors are needed for this purpose. In this work, different architectures of semiconductor distributed Bragg reflectors (DBR) are assessed as the appropriate choice for application in monolithic multijunction solar cells. Since the photon re-emission in the photon recycling process is spatially isotropic, the effect of the incident angle on the reflectance spectrum is of central importance. In addition, the DBR structure must be designed taking into account its integration into the monolithic multijunction solar cells, concerning series resistance, growth economics, and other issues. We analyze the tradeoffs in DBR design complexity with all these requirements to determine if such a reflector is suitable to improve multijunction solar cells.

关键词：电子信息；半导体；单片；太阳能电池

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The National Research Council's (NRC) Decadal Survey (DS) of Earth Science and Applications from Space has identified the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) as an important atmospheric science mission. NASA Langley Research Center, working with its partners, is developing fiber laser architecture based intensity modulated CW laser absorption spectrometer for measuring XCO2 in the 1571 nm spectral band. In support of this measurement, remote sensing of O2 in the 1260 nm spectral band for surface pressure measurements is also being developed. In this paper, we will present recent progress made in the development of advanced transmitter modules for CO2 and O2 sensing. Advanced DFB seed laser modules incorporating low-noise variable laser bias current supply and low-noise variable temperature control circuit have been developed. The 1571 nm modules operate at 80 mW and could be tuned continuously over the wavelength range of 1569-1574nm at a rate of 2 pm/mV. Fine tuning was demonstrated by adjusting the laser drive at a rate of 0.7 pm/mV. Heterodyne linewidth measurements have been performed showing linewidth (approximately)200 kHz and frequency jitter (approximately)75 MHz. In the case of 1260 nm DFB laser modules, we have shown continuous tuning over a range of 1261.4 - 1262.6 nm by changing chip operating temperature and 1261.0 - 1262.0 nm by changing the laser diode drive level. In addition, we have created a new laser package configuration which has been shown to improve the TEC coefficient of performance by a factor of 5 and improved the overall efficiency of the laser module by a factor of 2.

关键词：电子信息；半导体；激光发射；低交换

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NEPP focus: Evaluate alternative power devices forspace applications.New technologies; New suppliers.This talk:Silicon power MOSFETs;  part 1 (GSFC). NASA Electronic Parts and Packaging Program (NEPP) Electronics Technology Workshop (ETW), NASA GSFC, June 13, 2012. Other talks during this NEPP ETW:Silicon – part 2 (JPL); Gallium Nitride; Silicon Carbide.

关键词：电子信息；半导体；晶体管；氧化物

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This document is our final technical report and describes the efforts under contract N00014-11-1-0521. The objective of this work was to establish the feasibility of creating solution processed metamaterials formed from composites of semiconductor quantum dots (QDs). The specific goals of this work included, (1) modeling of the metamaterial's optical properties, (2) developing fabrication techniques and (3) experimental characterization of the materials' optical properties. Modeling was first conducted and it was found that under ideal conditions, a high frequency magnetic response could be created in metamaterials formed from composites of quantum dots utilizing excitonic resonances. However, in experimentally fabricated films using cadmium selenide QDs, it was found that the excitonic resonance is significantly broadened, preventing the high index needed to realize metamaterials with tailored effective permittivity and permeability. To overcome this challenge, lead sulfide QDs were then explored due to their high bulk index. Using lead sulfide QDs it was found that a considerably higher effective constituent index could be achieved. However, it was found that thick QD films and multilayer films could not be realized without inducing severe cracking. Patterning of multilayer films was achieved but due to their thin thickness, optical resonances could not be supported.

关键词：电子信息；半导体；纳米材料；低损耗

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A combination of rising energy costs, a desire for national energy independence, and a growing awareness of the dangers of global climate change is pushing Americans to do what they can to save energy. Consumers now buy more fuel-efficient cars and appliances and are growing more aware of their use habits. While it is easy to see how much gas your car uses, beyond the labeling on major appliances at the point of sale, most consumers are unaware of how much electricity these devices actually use. In this Masters of Engineering Capstone Project we designed and implemented a wireless power monitor which sits on a conventional power outlet and is thin enough that an appliance plugs throughs. The power of the appliance being plugged through our device is monitored. The monitor is powered by either making direct contact with the prongs of the plug or by inductively harvesting through a contactless transformer. The latter case puts severe power restrictions on the mote which we overcame by using low-power hardware and OpenWSN, a network stack intended for low power, low data-rate applications such as ours.

关键词：能量收集；无线电力监控；无线网络；无线传感器网络基础平台

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In this paper, we first focus on four different interaction techniques to share and manipulate content on large displays by using mobile phones. We compare speed and accuracy of these techniques by gathering and analyzing data from a user study with ten participants. From the data, we find touchpad is the most appropriate interaction technique, so we choose touchpad as our primary technique for developing applications. Our approach is to execute multiple copies of several existing applications in parallel and keep them synchronized, and they can be used by multiple users through touchpad interaction. Finally, we conduct a user study with ten participants to interact with our system. The evaluation result shows that it is convenient and efficient to use our system in a collaborative environment.

关键词：交互技术；大型显示屏；触摸屏

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We present the results of a two-year early career LDRD that focused on defect localization in deep green and deep ultraviolet (UV) light-emitting diodes (LEDs). We describe the laser-based techniques (TIVA/LIVA) used to localize the defects and interpre.

关键词：电子信息；半导体；LED；失效模式

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A  compact  and  robust  magnetic  label  detector  for  biomedical  assays  is implemented  in  0.18-μm  CMOS.    No  external  magnet,  reference  sensor  or  baseline calibration  is  required.  Detection  relies  on  the  magnetic  relaxation  signature  of  a microbead label for improved tolerance to environmental variations and relaxed dynamic range  requirement.

关键词：磁传感器芯片；CMOS；生物医学；医疗器械

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This whitepaper shows that it is now technically possible to reliably store and analyze 1 million genomes and related clinical and pathological data, which would match the demand for 2014. Moreover, thanks to advances in cloud computing, it is surprisingly affordable: multiple estimates agree on a technology cost of about $25 a year per genome.While the focus is on technology, to be thorough, this whitepaper touches on high-level policy issues as well as low-level details about statistics and the price of computer memory to cover the scope of the issues that a million cancer genome warehouse raises.

关键词：基因组测序；基因组；生物医学；内存覆盖；云计算；软件；硬件

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The constant pace of CMOS technology scaling has enabled continuous improvement in integrated-circuit cost and functionality, generating a new paradigm shift towards mobile computing. However, as the MOSFET dimensions are scaled below 30nm, electrostatic integrity and device variability become harder to control, degrading circuit performance. In order to overcome these issues, device engineers have started transitioning from the conventional planar bulk MOSFET toward revolutionary thin-body transistor structures such as the FinFET or fully-depleted silicon-on-insulator (FDSOI) MOSFET. While these alternatives appear to be elegant solutions, they require increased process complexity and/or more expensive starting substrates, making development and manufacturing costs a concern. For certain applications (such as mobile electronics), cost is still an important factor, inhibiting the quick adoption of the FinFET and FDSOI MOSFET structures while providing an opportunity to extend the competitiveness of planar bulk-silicon CMOS. A segmented-channel MOSFET (SegFET) design, which combines the benefits of both planar bulk MOSFETs (i.e. lower process complexity and/or cost) and thin-body transistor structures (i.e. improved electrostatic integrity), can provide an evolutionary pathway to enable the continued scaling of planar bulk technology below 20nm. In this work, experimental results comparing SegFETs and planar MOSFETs show suppressed short-channel effects and comparable on-state current (despite halving the effective device width). 

关键词：CMOS；薄身晶体管结构；全耗硅绝缘体；分段通道

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