نتایج جستجو برای: qws

تعداد نتایج: 319  

Journal: :Optics express 2011
Hongping Zhao Guangyu Liu Jing Zhang Jonathan D Poplawsky Volkmar Dierolf Nelson Tansu

Optimization of internal quantum efficiency (IQE) for InGaN quantum wells (QWs) light-emitting diodes (LEDs) is investigated. Staggered InGaN QWs with large electron-hole wavefunction overlap and improved radiative recombination rate are investigated for nitride LEDs application. The effect of interface abruptness in staggered InGaN QWs on radiative recombination rate is studied. Studies show t...

Journal: :Optics letters 2012
Huimin Lu Tongjun Yu Gangcheng Yuan Xinjuan Chen Zhizhong Chen Genxiang Chen Guoyi Zhang

The optical polarization properties of staggered AlGaN-AlGaN/AlN quantum wells (QWs) are investigated using the theoretical model based on the k·p method. The numerical results show that the energy level order and coupling relation of the valence subband structure change in the staggered QWs and the trend is beneficial to TE polarized transition compared to that of conventional AlGaN/AlN QWs. A...

2007
H. X. Jiang

Both a-plane and c-plane AlN/Al0.65Ga0.35N quantum wells QWs have been grown by metal organic chemical vapor deposition and their photoluminescence PL emission properties were studied and compared. It was found that the low temperature PL characteristics of a-plane QWs are primarily governed by the quantum size effect, whereas those of c-plane QWs are significantly affected by the polarization ...

Journal: :Ultramicroscopy 2017
C J Humphreys J T Griffiths F Tang F Oehler S D Findlay C Zheng J Etheridge T L Martin P A J Bagot M P Moody D Sutherland P Dawson S Schulz S Zhang W Y Fu T Zhu M J Kappers R A Oliver

We have used high resolution transmission electron microscopy (HRTEM), aberration-corrected quantitative scanning transmission electron microscopy (Q-STEM), atom probe tomography (APT) and X-ray diffraction (XRD) to study the atomic structure of (0001) polar and (11-20) non-polar InGaN quantum wells (QWs). This paper provides an overview of the results. Polar (0001) InGaN in QWs is a random all...

2016
H. S. Mączko R. Kudrawiec M. Gladysiewicz

It is shown that compressively strained Ge1-xSnx/Ge quantum wells (QWs) grown on a Ge substrate with 0.1 ≤ x ≤ 0.2 and width of 8 nm ≤ d ≤ 14 nm are a very promising gain medium for lasers integrated with an Si platform. Such QWs are type-I QWs with a direct bandgap and positive transverse electric mode of material gain, i.e. the modal gain. The electronic band structure near the center of Bril...

2016
Jinling Yu Xiaolin Zeng Shuying Cheng Yonghai Chen Yu Liu Yunfeng Lai Qiao Zheng Jun Ren

The ratio of Rashba and Dresselhaus spin splittings of the (001)-grown GaAs/AlGaAs quantum wells (QWs), investigated by the spin photocurrent spectra induced by circular photogalvanic effect (CPGE) at inter-band excitation, has been effectively tuned by changing the well width of QWs and by inserting a one-monolayer-thick InAs layer at interfaces of GaAs/AlGaAs QWs. Reflectance difference spect...

2007
A. Aierken T. Hakkarainen J. Tiilikainen M. Mattila J. Riikonen M. Sopanen H. Lipsanen

The growth and surface passivation of near-surface InGaAs quantum wells (QWs) on GaAs (1 1 0) substrate have been investigated. Triangular shaped small islands, approximate areal density of 10 cm , are observed on metal organic vapor phase epitaxially grown GaAs single layer and InGaAs multi-quantum wells (MQWs) surfaces in a wide range of growth temperatures. By optimizing the growth condition...

2018
Carol H Wysham Julio Rosenstock Marion L Vetter Fang Dong Peter Öhman Nayyar Iqbal

AIMS To simplify administration of aqueous exenatide once weekly, which requires reconstitution, the exenatide microspheres have been reformulated in a ready-to-use autoinjector with a Miglyol diluent (exenatide QWS-AI). This study compared the efficacy and safety of exenatide QWS-AI with the first-in-class glucagon-like peptide-1 receptor agonist exenatide twice daily (BID). MATERIALS AND ME...

Journal: :CoRR 2013
Giuseppe Di Molfetta Marc Brachet Fabrice Debbasch

QWs are simple formal analogues of classical random walks. They have been first considered by Feynman [1] as possible discretizations of the free Dirac dynamics in flat space-time. They have been introduced in the physics literature by [2] and [3] and the continuous-time version first appeared in [4] . They have been realized experimentally in [5–12] and are important in many fields, ranging fr...

2014
Jinling Yu Shuying Cheng Yunfeng Lai Qiao Zheng Yonghai Chen

: Spin photocurrent spectra induced by Rashba- and Dresselhaus-type circular photogalvanic effect (CPGE) at inter-band excitation have been experimentally investigated in InGaAs/GaAs/AlGaAs step quantum wells (QWs) at room temperature. The Rashba- and Dresselhaus-induced CPGE spectra are quite similar with each other during the spectral region corresponding to the transition of the excitonic st...

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