Search query: OPTICAL semiconductor devices for LED LIGHT

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abstract: Abstract. A silicon p channel metal oxide semiconductor field effect transistor (Si PMOSFET) that is fully compatible with the standard complementary metal oxide semiconductor process is investigated based on the phenomenon of optical radiation observed in the reverse biased p n junction in the Si PMOSFET device. The device can be used either as a two terminal silicon diode light emitting device (Si diode LED) or as a three terminal silicon gate controlled diode light emitting device (Si gate controlled diode LED) It is seen that the three terminal operating mode could provide much higher power transfer efficiency than the two terminal operating mode. A new solution based on the concept of a theoretical quantum efficiency model combined with calculated results is proposed for interpreting the evidence of light intensity reduction at high operating voltages. The Si LED that can be easily integrated into CMOS fabrication process is an important step toward optical interconnects.
author_names: Kaikai Xu
title: Structural and optical properties of silicon metal oxide semiconductor light emitting devices
year: 2016

abstract: We demonstrated a new kind of InGaN/GaN multi quantum well (MQW) light emitting diode (LED) with simplified fabrication processes, where only one round of photolithography and electrode deposition is necessary. The electrical and optical properties of this LED, which is defined as a coplanar metal semiconductor metal (CMSM) LED, were characterized. The electroluminescence spectrum only exhibits blue emission at 450 nm, meaning that the light comes exclusively from MQWs. The optical output at 20 mA was comparable to that of conventional LEDs. A shunt circuit model with a surface thin film resistance, an n+ InGaN/p GaN/n GaN structure and a p GaN/n GaN junction was proposed to explain the working mechanism of the CMSM LED. A proof of concept display was demonstrated, exploiting the promising application of CMSM LED to display.
author_names: Hao Long

Y P Zeng

Yang Mei

Leiying Ying

Baoping Zhang
title: Coplanar metal semiconductor metal light emitting devices with an n+ InGaN layer and their application to display
year: 2016

abstract: The reflectivity versus incident angle of a GaP/Au reflector, a GaP/SiO2/Au triple ODR (omni directional reflector) and a GaP/ITO/Au triple ODR was calculated. Compared to AlGaInP LEDs with a GaAs absorbing substrate, thin film LEDs with a Au reflector, a SiO2 ODR and an ITO ODR were fabricated. At a current of 20 mA, the optical output power of four samples was respectively 1.04, 1.14, 2.53 and 2.15 mW. The Au diffusion in the annealing process reduces the reflectivity of the Au/GaP reflector to 9% The different transmittance of quarter wave thickness ITO and SiO2 induces different optical output power between the SiO2 and ITO thin film LEDs. The insertion of Zn in the ITO ODR LED does not affect the light output but evidently reduces the voltage.
author_names: Wei Gao

Weiling Guo

DeShu Zou

Qin Yuan

Wenxin Jiang

Guangdi Shen
title: SEMICONDUCTOR DEVICES Thin film AlGaInP light emitting diodes with different reflectors
year: 2010

abstract: In order to further improve the efficiency and the spectral quality of white light LEDs new colour conversion materials which allow a selective and narrow banded conversion of the blue excitation light are needed. Quantum dots could be promising in this regard as they exhibit exactly these properties. For commercially used light sources a stable colour distribution has to be ensured over the entire lifetime. Our experiments revealed a very different degradation characteristic of phosphor and quantum dots. In this paper we present the results of different experiments which aim on the understanding of the mechanism for optical stability. We focused mainly on two degradation effects, a decrease of the photoluminescence intensity and a shift of the emission peak wavelength towards the blue.
author_names: David Schmidmayr

Johann Zehetner

Peter Amann
title: Investigation of optical stability issues with embedded semiconductor quantum dots used as colour conversion material in LED lighting applications
venue: The Tenth International Conference on Advanced Semiconductor Devices and Microsystems
year: 2014

abstract: In order to ensure the exchangeability of LED light engines in LED based luminaires, the Zhaga consortium develops standard specifications for the interfaces of LED light engines. The complete interface definition consists of the description of a mechanical, optical, electrical and thermal interface. The thermal interface has to ensure a good thermal contact between the engine and the fixture. Next to that, the heat spreading capabilities of both the engine and the fixture have to be taken into account in order to ensure sufficient heat spreading capabilities of complete luminaire. In order to come to a practical interface definition, a number of tests and test devices are proposed. Engines and fixture have to pass these tests in order to become Zhaga compliant. One test is the heat flux measurement on the LED light engine in order to determine the amount of heat that has to be transferred from the engine via the fixture. The second test is a test with a reference thermal engine in order to determine the heat spreading capabilities and the thermal resistance of a fixture. The final test is a test with a reference luminaire in order to determine the heat spreading capabilities of the LED light engine. With these three tests, we can realize a practical thermal interface definition.
author_names: T C Treurniet

Karel Joop Bosschaart
title: Method for heat flux measurement on LED light engines
venue: 2011 27th Annual IEEE Semiconductor Thermal Measurement and Management Symposium
year: 2011

abstract: The optical semiconductor unit of the present invention has an LED device, the LED device is provided with a light emitting diode (LED) and a socket, said socket mounted on the light emitting diode, LED devices having a body, LED mounted on the body, the body having a first surface, bulk electrode connected to the first surface portion.
title: The optical semiconductor device, the optical semiconductor element and the socket
year: 2010

abstract: The determination to develop fast, efficient devices has led to vast studies on photonic circuits but it is difficult to shrink these circuits below the diffraction limit of light. However, the coupling between surface plasmon polaritons and nanostructures in the near field shows promise in developing next generation integrated circuitry. In this work, we demonstrate the potential for integrating nanoplasmonic based light guides with atomically thin materials for on chip near field plasmon detection. Specifically, we show near field electrical detection of silver nanowire plasmons with the atomically thin semiconductor molybdenum disulfide. Unlike graphene, atomically thin semiconductors such as molybdenum disulfide exhibit a bandgap that lends itself for the excitation and detection of plasmons. Our fully integrated plasmon detector exhibits plasmon responsivities of ~255 mA/W that corresponds to highly efficient plasmon detection ~0.5 electrons per plasmon)
author_names: Kenneth M Goodfellow

Chitraleema Chakraborty

Ryan Beams

Lukas Novotny

A Nick Vamivakas
title: Direct On Chip Optical Plasmon Detection with an Atomically Thin Semiconductor.
venue: Nano letters
year: 2015

abstract: Colloidal semiconductor nanocrystals, also known as "quantum dots" (QDs) represent an example of a disruptive technology for display and lighting applications. The QDs' high luminescence efficiency and precisely tunable, narrow emission are nearly ideal for achieving saturated colors and enriching the display or TV color gamut. Quantum dot light emitting diodes (QLEDs) can provide saturated emission colors and allow inexpensive solution based device fabrication on almost any substrate. The first incorporation of QDs into the consumer market is using them as optical down converters. Blue light from an efficient high energy light source (e.g. GaN blue LED) is absorbed and reemitted at any desired lower energy wavelength. Alternatively, electric current can be used for direct excitation of QDs. QLEDs are an exciting technical challenge and commercial opportunity for display and solid state lighting applications. Recent developments in the field show that efficiency and brightness of QLEDs can match those of organic LEDs.
author_names: Dmitri V Talapin

Jonathan S Steckel
title: Quantum dot light emitting devices
year: 2013

abstract: The power output, forward voltage, conversion efficiency, and spectral characteristics of a 365 nm ultraviolet light emitting diode (LED) were measured for applications of triggering wide bandgap photoconductive switches for pulsed power applications. Pulsed currents through the LED ranged from 125 mA up to 2.2 A at widths from 10 ms up to several seconds. Using time resolved electroluminescence spectroscopy, peak emission was observed to occur at 368.5 nm for short pulses with a red shift to 371.8 nm for pulses 8 s in duration. A peak light output of 4.1 W was measured for short pulses ;50 ms) of 2.12 A, corresponding to six times the rated output specification. The LED was used to trigger a high voltage photoconductive semiconductor switch (PCSS) at voltages up to 6 kV into a high impedance load. The 365 nm LED is a promising candidate for optical triggering of PCSS devices.
author_names: Daniel Mauch

Cameron Hettler

William Sullivan

Andreas A Neuber

James C Dickens
title: Evaluation of a Pulsed Ultraviolet Light Emitting Diode for Triggering Photoconductive Semiconductor Switches
venue: IEEE Transactions on Plasma Science
year: 2015

abstract: GaN and related materials have received a lot of attention because of their applications in a number of semiconductor devices such as LEDs, laser diodes, field effect transistors, photodetectors etc. An introduction to optical phenomena in semiconductors, light emission in p n junctions, evolution of LED technology, bandgaps of various semiconductors that are suitable for the development of LEDs are discussed first. The detailed discussion on photoluminescence of GaN nanostructures is made, since this is crucial to develop optical devices. Fabrication technology of many nanostructures of GaN such as nanowires, nanorods, nanodots, nanoparticles, nanofilms and their luminescence properties are given. Then the optical processes including ultrafast phenomena, radiative, non radiative recombination, quantum efficiency, lifetimes of excitons in InGaN quantum well are described. The LED structures based on InGaN that give various important colors of red, blue, green, and their design considerations to optimize the output were highlighted. The recent efforts in GaN technology are updated. Finally the present challenges and future directions in this field are also pointed out.
author_names: Annamraju Kasi Viswanath
title: GaN nanostructure based light emitting diodes and semiconductor lasers.
venue: Journal of nanoscience and nanotechnology
year: 2014