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We report on a dynamic photoconductive gain effect in quantum wires which are lithographically fabricated in an AlGaAs/GaAs quantum well via a shallow-etch technique. The effect allows resolving the one-dimensional subbands of the quantum…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 K. -D. Hof , C. Rossler , S. Manus , J. P. Kotthaus , A. W. Holleitner , D. Schuh , W. Wegscheider

This work studies the effect of temperature on the binding energy of a shallow hydrogenic impurity located on the axis of a cylindrical semiconductor GaAs Al_x Ga_{1-x} As quantum well wire. The results show that the binding energy at a low…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 T G Emam

We report a persistent increase or decrease in the two-dimensional electron density of AlAs or GaAs quantum wells flanked by AlGaAs barriers, brought about by illuminating the samples at T ~ 4 K while simultaneously applying a voltage bias…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 E. P. De Poortere , Y. P. Shkolnikov , M. Shayegan

We propose a compact high-intensity room-temperature source of entangled photons based on the efficient second-order process of two-photon spontaneous emission from electrically-pumped semiconductor quantum wells in a photonic microcavity.…

Quantum Physics · Physics 2009-11-13 Alex Hayat , Pavel Ginzburg , Meir Orenstein

The growth-diection quantization of confined electron gas in a GaAs/AlGaAs based quantum well structure is obtained in the Kohn-Sham iterative computational scheme. The longitudinal conductance at low temperatures, in the presence of…

Mesoscale and Nanoscale Physics · Physics 2009-01-14 Partha Goswami , Garima Puneyani , Avinashi Kapoor

The photocurrent and the small-signal photoconductance of InGaN/GaN multiple-quantum-well structures were studied at the temperature range from 10 to 300 K. The optical excitation was carried out at the quantum wells intrinsic absorption…

Mesoscale and Nanoscale Physics · Physics 2014-04-10 M. V. Baranovskiy , G. F. Glinskii , M. S. Mironova

The effects of low temperature illumination and annealing on fractional quantum Hall (FQH) characteristics of a GaAs/AlGaAs quantum well are investigated. Illumination alone, below 1 K, decreases the density of the 2DEG electrons by more…

We study the structural, optical, and transport properties of sidewall quantum wires on GaAs(001) substrates. The QWRs are grown by molecular beam epitaxy (MBE) on GaAs(001) substrates prepatterned with shallow ridges. They form as a…

Mesoscale and Nanoscale Physics · Physics 2019-06-19 Paul L. J. Helgers , Haruki Sanada , Yoji Kunihashi , Klaus Biermann , Paulo V. Santos

We demonstrate gain in a three-dimensional metal/semiconductor metamaterial by the integration of optically active semiconductor quantum structures. The rolling-up of a metallic structure on top of strained semiconductor layers containing a…

InGaAs/GaAsBi/InGaAs quantum wells (QWs) were grown on GaAs substrates by gas source molecular beam epitaxy for realizing the type II band-edge line-up. Both type I and type II transitions were observed in the Bi containing W QWs and the…

Materials Science · Physics 2016-09-21 Wenwu Pan , Liang Zhu , Liyao Zhang , Yaoyao Li , Peng Wang , Xiaoyan Wu , Fan Zhang , Jun Shao , Shumin Wang

Over the past two decades, epitaxial semiconductor quantum dots (QDs) have demonstrated very promising properties as sources of single photons and entangled photons on-demand. Among different growth methods, droplet etching epitaxy has…

We report measurements of the compressibility of a one-dimensional (1D) quantum wire, defined in the upper well of a GaAs/AlGaAs double quantum well heterostructure. A wire defined simultaneously in the lower well probes the ability of the…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 L. W. Smith , A. R. Hamilton , K. J. Thomas , M. Pepper , I. Farrer , J. P. Griffiths , G. A. C. Jones , D. A. Ritchie

We present net gain measurements at room temperature in Al$_{0.07}$Ga$_{0.93}$N/GaN 10-period multi-quantum well emitting at 367 nm, using the variable stripe length method. Measurements were conducted at two different positions on the…

We report on time-resolved and steady-state photoluminescence studies of GaAs/AlGaAs V-groove quantum wire structures. Steady-state photoluminescence experiments are performed in the temperature range from 8K to 200K. We evaluate the…

Materials Science · Physics 2015-06-25 D. Y. Oberli , F. Vouilloz , R. Ambigapathy , B. Deveaud , E. Kapon

We observed room-temperature intersubband transitions at 1.26 microns in n-doped type-II In$_{0.3}$Ga$_{0.7}$As/AlAs strained quantum wells. An improved tight-binding model was used to optimize the structure parameters in order to obtain…

A design strategy for achieving broadband optical gain in GaSb-based semiconductor amplifiers operating beyond 2 \mu m is presented. By employing asymmetric GaInSb/AlGaAsSb quantum wells (QWs) of varying thicknesses, a flat and wide gain…

Modulation-doped GaAs v-groove quantum wires (QWRs) have been fabricated with novel electrical contacts made to two-dimensional electron-gas (2DEG) reservoirs. Here, we present longitudinal photocurrent (photoconductivity/PC) spectroscopy…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 N. I. Cade , M. Hadjipanayi , R. Roshan , A. C. Maciel , J. F. Ryan , F. Macherey , Th. Schaepers , H. Lueth

We report measurements of radiation transmission in the 0.220--0.325 THz frequency domain through GaN quantum wells grown on sapphire substrates at room and low temperatures. A significant enhancement of the transmitted beam intensity with…

We report on the influence of the quantum well thickness on the effective band gap and conversion efficiency of In0.12Ga0.88N/GaN multiple quantum well solar cells. The band-to-band transition can be redshifted from 395 to 474 nm by…

Mesoscale and Nanoscale Physics · Physics 2016-02-24 L. Redaelli , A. Mukhtarova , S. Valdueza-Felip , A. Ajay , C. Bougerol , C. Himwas , J. Faure-Vincent , C. Durand , J. Eymery , E. Monroy

By selective doping (Be) of the well and barrier regions of p-GaAs/AlGaAs structures we have realized the situation where the upper Hubbard band (A+ centers) has been occupied by holes in the equilibrium. We studied temperature behavior of…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 N. V. Agrinskaya , Yu. L. Ivanov , P. V. Petrov , V. M. Ustinov
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