English
Related papers

Related papers: Surface segregation and the Al problem in GaAs qua…

200 papers

We introduce a design of electrically isolated floating bilayer GaAs quantum wells (QW) in which application of a large gating voltage controllably and highly reproducibly induces charges that remain trapped in the bilayer after removal of…

Mesoscale and Nanoscale Physics · Physics 2021-06-16 Joonho Jang , Heun Mo Yoo , Loren N. Pfeiffer , Kenneth W. West , K. W. Baldwin , Raymond C. Ashoori

We report on the growth and electrical characterization of a series of two-dimensional hole systems (2DHSs) used to study the density dependence of low temperature mobility in 20 nm GaAs/AlGaAs quantum wells. The hole density was controlled…

Mesoscale and Nanoscale Physics · Physics 2012-04-26 J. D. Watson , S. Mondal , G. Gardner , G. A. Csáthy , M. J. Manfra

We report quantum dots fabricated on very shallow 2-dimensional electron gases, only 30 nm below the surface, in undoped GaAs/AlGaAs heterostructures grown by molecular beam epitaxy. Due to the absence of dopants, an improvement of more…

Mesoscale and Nanoscale Physics · Physics 2015-03-19 W. Y. Mak , F. Sfigakis , K. Das Gupta , O. Klochan , H. E. Beere , I. Farrer , J. P. Griffiths , G. A. C. Jones , A. R. Hamilton , D. A. Ritchie

High mobility two-dimensional electron gases (2DEGs) underpin today's silicon based devices and are of fundamental importance for the emerging field of oxide electronics. Such 2DEGs are usually created by engineering band offsets and charge…

Strongly Correlated Electrons · Physics 2016-12-13 S. McKeown Walker , F. Y. Bruno , F. Baumberger

The growth and the density dependence of the low temperature mobility of a series of two-dimensional electron systems confined to un-intentionally doped, low extended defect density InAs quantum wells with Al$_{1-x}$Ga$_{x}$Sb barriers are…

GaAs-based two-dimensional electron gases (2DEGs) show a wealth of remarkable electronic states, and serve as the basis for fast transistors, research on electrons in nanostructures, and prototypes of quantum-computing schemes. All these…

Mesoscale and Nanoscale Physics · Physics 2010-09-21 M. P. Jura , M. A. Topinka , L. Urban , A. Yazdani , H. Shtrikman , L. N. Pfeiffer , K. W. West , D. Goldhaber-Gordon

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…

In low-disorder, two-dimensional electron systems (2DESs), the fractional quantum Hall states at very small Landau level fillings ($\nu$) terminate in a Wigner solid (WS) phase, where electrons arrange themselves in a periodic array. The WS…

Mesoscale and Nanoscale Physics · Physics 2024-01-25 P. T. Madathil , K. A. Villegas Rosales , Y. J. Chung , K. W. West , K. W. Baldwin , L. N. Pfeiffer , L. W. Engel , M. Shayegan

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 have investigated the conditions necessary to achieve stronger Cherenkov-like instability of plasma waves leading to emission in the terahertz (THz) regime for semiconductor quantum wells (QWs). The surface response function is…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 Antonios Balassis , Godfrey Gumbs

The GaAs/AlGaAs quantum well solar cell (QWSC) shows promise as a novel approach to higher efficiency solar cells but suffers from a poor short circuit current Jsc. We report on efforts to reduce this problem with the use of compositional…

Mesoscale and Nanoscale Physics · Physics 2016-06-14 James P. Connolly , Keith W. J. Barnham , Jenny Nelson , Christine Roberts , Malcolm Pate , John S. Roberts

High mobility, strong spin-orbit coupling, and large Land\'e g-factor make the two-dimensional electron gas (2DEG) in InAs quantum wells grown on nearly-lattice-matched GaSb substrates an attractive platform for mesoscopic quantum transport…

Mesoscale and Nanoscale Physics · Physics 2018-10-24 C. Thomas , A. T. Hatke , A. Tuaz , R. Kallaher , T. Wu , T. Wang , R. E. Diaz , G. C. Gardner , M. A. Capano , M. J. Manfra

We report in this letter experimental results that confirm the two-dimensional nature of the electron systems in monolayer InN quantum wells embedded in GaN barriers. The electron density and mobility of the two-dimensional electron system…

Mesoscale and Nanoscale Physics · Physics 2015-06-22 W. Pan , E. Dimakis , G. T. Wang , T. D. Moustakas , D. C. Tsui

The two-dimensional electron gas (2DEG) found in KTaO3-based interfaces has garnered attention due to its remarkable electronic properties. In this study, we investigated the conducting system embedded at the Si3N4/Al//KTO(110)…

The geometry of quantum wells (QWs) critically influences carrier mobility, yet systematic comparisons between finite and infinite square QWs remain scarce. We present a comprehensive study of GaAs/In$_x$Ga$_{1-x}$As/GaAs heterostructures…

Mesoscale and Nanoscale Physics · Physics 2025-05-21 Truong Van Tuan , Nguyen Dung Chinh , Tran Trong Tai , Vo Van Tai , Nguyen Duy Vy

The precise control of a bilayer system consisting of two adjacent two-dimensional electron gases (2DEG) is demonstrated by using a novel planar back-gate approach based on ion implantation. This technique overcomes some common problems of…

Mesoscale and Nanoscale Physics · Physics 2020-08-26 J. Scharnetzky , J. M. Meyer , M. Berl , C. Reichl , L. Tiemann , W. Dietsche , W. Wegscheider

We report the observation of Shubnikov-de Haas (SdH) oscillations in coherently strained, low-dislocation AlN/GaN/AlN quantum wells (QWs), including both undoped and $\delta$-doped structures. SdH measurements reveal a single subband…

Materials Science · Physics 2025-02-12 Yu-Hsin Chen , Jimy Encomendero , Huili Grace Xing , Debdeep Jena

The two-dimensional electron gas residing in shallow InAs quantum wells coupled to epitaxial aluminum is a widely utilized platform for exploration of topological superconductivity. Strong spin-orbit coupling, large effective $g$-factor,…

Mesoscale and Nanoscale Physics · Physics 2024-12-17 Teng Zhang , Tyler Lindemann , Geoffrey C. Gardner , Sergei Gronin , Tailung Wu , Michael J. Manfra

We have investigated experimentally the magnetoresistance of strongly asymmetric double-wells. The structures were prepared by inserting a thin Al$_{0.3}$Ga$_{0.7}$As barrier into the GaAs buffer layer of a standard modulation-doped…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Yu. Krupko , L. Smrcka , P. Vasek , P. Svoboda , M. Cukr , L. Jansen

Segregation and dissolution behavior of Mg alloyed with Ca and Al are studied by performing density functional theory calculations considering an extensive set of surface structures and compositions. Combining ab initio surface science…

Materials Science · Physics 2026-04-03 Jing Yang , K. B. Sravan Kumar , Mira Todorova , Jörg Neugebauer