Carrier Transport Study of TMIn-Treated InGaN LEDs by Using Quantum Efficiency and Time-Resolved Electro-Luminescence Measurements

2012 ◽  
Vol 159 (3) ◽  
pp. H225-H229 ◽  
Author(s):  
Shih-Wei Feng ◽  
Jen-Inn Chyi
Keyword(s):  
Quantum Efficiency ◽  
Carrier Transport ◽  
Time Resolved ◽  
Transport Study ◽  
Electro Luminescence

scholarly journals Designs of InGaN Micro-LED Structure for Improving Quantum Efficiency at Low Current Density

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Shiqiang Lu ◽  
Jinchai Li ◽  
Kai Huang ◽  
Guozhen Liu ◽  
Yinghui Zhou ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Current Density ◽  
Carrier Transport ◽  
Defect Density ◽  
Numerical Study ◽  
Structure Design ◽  
Operating Conditions ◽  
Hole Injection ◽  
Electron Blocking Layer ◽  
Recombination Processes

AbstractHere we report a comprehensive numerical study for the operating behavior and physical mechanism of nitride micro-light-emitting-diode (micro-LED) at low current density. Analysis for the polarization effect shows that micro-LED suffers a severer quantum-confined Stark effect at low current density, which poses challenges for improving efficiency and realizing stable full-color emission. Carrier transport and matching are analyzed to determine the best operating conditions and optimize the structure design of micro-LED at low current density. It is shown that less quantum well number in the active region enhances carrier matching and radiative recombination rate, leading to higher quantum efficiency and output power. Effectiveness of the electron blocking layer (EBL) for micro-LED is discussed. By removing the EBL, the electron confinement and hole injection are found to be improved simultaneously, hence the emission of micro-LED is enhanced significantly at low current density. The recombination processes regarding Auger and Shockley–Read–Hall are investigated, and the sensitivity to defect is highlighted for micro-LED at low current density.Synopsis: The polarization-induced QCSE, the carrier transport and matching, and recombination processes of InGaN micro-LEDs operating at low current density are numerically investigated. Based on the understanding of these device behaviors and mechanisms, specifically designed epitaxial structures including two QWs, highly doped or without EBL and p-GaN with high hole concentration for the efficient micro-LED emissive display are proposed. The sensitivity to defect density is also highlighted for micro-LED.

Time-resolved Photoconductivity as a Probe of Carrier Transport in Microcrystalline Silicon

2006 ◽  
Vol 910 ◽  
Author(s):  
Steve Reynolds
Keyword(s):  
Density Of States ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Film Growth ◽  
Hole Mobility ◽  
Transport Parameters ◽  
Microcrystalline Silicon ◽  
Time Resolved ◽  
Transient Photoconductivity ◽  
Transport Measurements

AbstractThe use of transient photoconductivity techniques in the investigation of carrier transport in microcrystalline silicon is described. Results are presented which highlight variations in transport parameters such as carrier mobility and density of states with structure composition. Hole mobility is significantly enhanced by crystalline content in the film of 10% or less. The density of states inferred from transport measurements parallel to and at right angles to the direction of film growth differ somewhat, suggesting that transport may be anisotropic.

scholarly journals Enhancement of quantum efficiency in InGaN quantum wells by using superlattice interlayers and pulsed growth

2016 ◽  
Vol 55 (4) ◽  
Author(s):  
Kazimieras Nomeika ◽  
Mantas Dmukauskas ◽  
Ramūnas Aleksiejūnas ◽  
Patrik Ščajev ◽  
Saulius Miasojedovas ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Quantum Efficiency ◽  
Light Emitting Diode ◽  
Internal Quantum Efficiency ◽  
Recombination Coefficient ◽  
Time Resolved ◽  
Mocvd Growth ◽  
Lower Strain ◽  
Type Contact ◽  
Ingan Quantum Wells

Enhancement of internal quantum efficiency (IQE) in InGaN quantum wells by insertion of a superlattice interlayer and applying the pulsed growth regime is investigated by a set of time-resolved optical techniques. A threefold IQE increase was achieved in the structure with the superlattice. It was ascribed to the net effect of decreased internal electrical field due to lower strain and altered carrier localization conditions. Pulsed MOCVD growth also resulted in twice higher IQE, presumably due to better control of defects in the structure. An LED (light emitting diode) structure with a top p-type contact GaN layer was manufactured by using both growth techniques with the peak IQE equal to that in the underlying quantum well structure. The linear recombination coefficient was found to gradually increase with excitation due to carrier delocalization, and the latter dependence was successfully used to fit the IQE droop.

Comparative Study of Photocarrier Dynamics in CVD-deposited CuWO4, CuO, and WO3 Thin Films for Photoelectrocatalysis

2020 ◽  
Vol 234 (4) ◽  
pp. 699-717
Author(s):  
James Hirst ◽  
Sönke Müller ◽  
Daniel Peeters ◽  
Alexander Sadlo ◽  
Lukas Mai ◽  
...  
Keyword(s):  
Thin Films ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Terahertz Spectroscopy ◽  
Chemical Vapor ◽  
Photoelectrochemical Cells ◽  
Time Resolved ◽  
And Diffusion ◽  
Wo3 Thin Films ◽  
Carrier Transport Properties

AbstractThe temporal evolution of photogenerated carriers in CuWO4, CuO and WO3 thin films deposited via a direct chemical vapor deposition approach was studied using time-resolved microwave conductivity and terahertz spectroscopy to obtain the photocarrier lifetime, mobility and diffusion length. The carrier transport properties of the films prepared by varying the copper-to-tungsten stoichiometry were compared and the results related to the performance of the compositions built into respective photoelectrochemical cells. Superior carrier mobility was observed for CuWO4 under frontside illumination.

Luminescence Intermittency and Quantum Efficiency of Individual Porous Si Nanoparticles.

1999 ◽  
Vol 560 ◽  
Author(s):  
Michael D. Mason ◽  
Grace M. Credo ◽  
Paul J. Carson ◽  
Steven K. Buratto
Keyword(s):  
Quantum Efficiency ◽  
Colloidal Suspension ◽  
Porous Si ◽  
Time Resolved ◽  
High Quantum Efficiency ◽  
Si Nanoparticles ◽  
Shear Force Microscopy ◽  
Spectrally Resolved ◽  
Single Particle Spectroscopy ◽  
Microscopy Techniques

ABSTRACTWe have recently observed spectrally resolved vibronic structure and luminescence intermittency from nanometer-size porous silicon nanocrystals. In this study we examine the quantum efficiency of a single nanoparticle and show that emitting nanoparticles do so with near unity quantum efficiency. This result suggests that the emission from porous Si nanoparticles, and thus bulk porous Si, results from a small number of high quantum efficiency emitters. In our previous work we have shown that our nanoparticles contain more than one coupled chromophore. In order to examine these effects more closely we employ several spectroscopy and microscopy techniques including: 1) single-particle spectroscopy, 2) shear-force microscopy, and 3) time-resolved spectroscopy, on a colloidal suspension of size-selected, surface-oxidized nanoparticles. In addition we apply statistical techniques to provide a more complete picture of the coupling between chromophores in a given nanoparticle.

Time-resolved measurement of free carrier absorption, diffusivity, and internal quantum efficiency in silicon

2013 ◽  
Vol 103 (9) ◽  
pp. 092101 ◽  
Author(s):  
Jet Meitzner ◽  
Frederick G. Moore ◽  
Brock M. Tillotson ◽  
Stephen D. Kevan ◽  
Geraldine L. Richmond
Keyword(s):  
Quantum Efficiency ◽  
Internal Quantum Efficiency ◽  
Free Carrier ◽  
Free Carrier Absorption ◽  
Time Resolved ◽  
Carrier Absorption

scholarly journals Time-Resolved Radiation-Induced Conductivity of Polyimide and Its Description Using the Multiple Trapping Formalism

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2061 ◽  
Author(s):  
Andrey Tyutnev ◽  
Vladimir Saenko ◽  
Aleksei Zhadov ◽  
Evgenii Pozhidaev
Keyword(s):  
Carrier Transport ◽  
Main Idea ◽  
Model Parameters ◽  
Mechanical And Thermal Properties ◽  
Current Sensing ◽  
Time Resolved ◽  
Multiple Trapping ◽  
Radiation Fluxes ◽  
Radiation Induced ◽  
Potential Decay

Polymer dielectrics subjected to intense radiation fluxes exhibit a radiation-induced conductivity (RIC). Polyimide is a good dielectric with excellent mechanical and thermal properties featuring high radiation resistance currently widely used in the spacecraft industry. Its RIC has been extensively studied in several laboratories. The purpose of the present study is to make a direct measurement of the RIC for both pulsed and continuous irradiation using a current sensing technique, which is contrary to the indirect method employing a surface-potential decay technique that is now preferred by spacecraft charging engineers. Our experiments are done in a small-signal regime excluding any recombination and dose effects. In combination with existing computer codes, we managed to develop further the conventional multiple trapping formalism and the RIC theory based on it. The main idea is to supplement an exponential trap distribution responsible for a dominant dispersive carrier transport in polymers with a small concentration of inherent deep traps which may or may not have an energy distribution. In line with this reasoning, we propose a tentative set of RIC model parameters for polyimide that accounts for the observed experimental data. The findings and their implications are discussed in a broad context of previous studies.

Time‐resolved luminescence study of ultrafast carrier transport in GaAs metal‐semiconductor‐metal devices

1993 ◽  
Vol 62 (7) ◽  
pp. 732-734 ◽  
Author(s):  
R. Kersting ◽  
J. Plettner ◽  
K. Leo ◽  
S. Averin ◽  
H. Kurz
Keyword(s):  
Carrier Transport ◽  
Time Resolved ◽  
Luminescence Study ◽  
Metal Semiconductor Metal ◽  
Ultrafast Carrier
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