Related papers: Surface segregation and the Al problem in GaAs qua…
Thanks to their multi-valley, anisotropic, energy band structure, two-dimensional electron systems (2DESs) in modulation-doped AlAs quantum wells (QWs) provide a unique platform to investigate electron interaction physics and ballistic…
We report transport mobility measurements for clean, two-dimensional (2D) electron systems confined to GaAs quantum wells (QWs), grown via molecular beam epitaxy, in two families of structures, a standard, symmetrically-doped GaAs set of…
We present in this work a simple Quantum Well (QW) structure consisting of GaAs wells with AlGaAs barriers as a probe for measuring the performance of arsine purifiers within a MetalOrganic Vapour Phase Epitaxy system. Comparisons between…
In modern GaAs/Al$_x$Ga$_{1-x}$As heterostructures with record high mobilities, a two-dimensional electron gas (2DEG) in a quantum well is provided by two remote donor $\delta$-layers placed on both sides of the well. Each $\delta$-layer is…
Modulation doped GaAs-AlGaAs quantum well based structures are usually used to achieve very high mobility 2-dimensional electron (or hole) gases. Usually high mobilities ($>10^{7}{\rm{cm}^{2}\rm{V}^{-1}\rm{s}^{-1}}$) are achieved at high…
The GaAs/AlGaAs materials system is well suited to multi-bandgap applications such as the multiple quantum well solar cell. GaAs quantum wells are inserted in the undoped AlGaAs active region of a pin structure to extend the absorption…
Degenerate conduction-band minima, or `valleys', in materials such as Si, AlAs, graphene, and MoS$_2$ allow them to host two-dimensional electron systems (2DESs) that can access a valley degree of freedom. These multivalley 2DESs present…
We calculate using the Boltzmann transport theory the density dependent mobility of two-dimensional (2D) electrons in GaAs, SiGe and AlAs quantum wells as well as of 2D holes in GaAs quantum wells. The goal is to precisely understand the…
Near-surface InAs two-dimensional electron gas (2DEG) systems have great potential for realizing networks of multiple Majorana zero modes towards a scalable topological quantum computer. Improving mobility in the near-surface 2DEGs is…
The quantum well solar cell (QWSC) is a p - i - n solar cell with quantum wells in the intrinsic region. Previous work has shown that QWSCs have a greater open circuit voltage (Voc) than would be provided by a cell with the quantum well…
Owing to their large effective mass, strong and tunable spin-orbit coupling, and complex band-structure, two-dimensional hole systems (2DHSs) in GaAs quantum wells provide rich platforms to probe exotic many-body physics, while also…
We have measured the surface acoustic wave velocity shift in a GaAs/AlGaAs heterostructure containing a two-dimensional electron system (2DES) in a low-density regime ($<$ $10^{10}$ cm$^{-2}$) at zero magnetic field. The interaction of the…
Two-dimensional electrons confined to GaAs quantum wells are hallmark platforms for probing electron-electron interaction. Many key observations have been made in these systems as sample quality improved over the years. Here, we present a…
Two dimensional electron gases (2DEGs) realized at GaAs/AlGaAs single interfaces by molecular-beam epitaxy (MBE) reach mobilities of about 15 million cm^2/Vs if the AlGaAs alloy is grown after the GaAs. Surprisingly, the mobilities may drop…
Gate-tunable high-mobility InSb/In_{1-x}Al_{x}Sb quantum wells (QWs) grown on GaAs substrates are reported. The QW two-dimensional electron gas (2DEG) channel mobility in excess of 200,000 cm^{2}/Vs is measured at T=1.8K. In asymmetrically…
We have observed an anomalous shift of the high field reentrant insulating phases in a two-dimensional electron system (2DES) tightly confined within a narrow GaAs/AlGaAs quantum well. Instead of the well-known transitions into the high…
In modern GaAs/Al$_x$Ga$_{1-x}$As heterostructures with record high mobilities, a two-dimensional electron gas (2DEG) in a quantum well is provided by two remote donor $\delta$-layers placed on both sides of the well. Each $\delta$-layer is…
We demonstrate a method of making a very shallow, gateable, undoped 2-dimensional electron gas. We have developed a method of making very low resistivity contacts to these structures and systematically studied the evolution of the mobility…
Candidate systems for topologically-protected qubits include two-dimensional electron gases (2DEGs) based on heterostructures exhibiting a strong spin-orbit interaction (SOI) and superconductivity via the proximity effect. For InAs- or…
Suppressing electron scattering is essential to achieve high-mobility two-dimensional electron systems (2DESs) that are clean enough to probe exotic interaction-driven phenomena. In heterostructures it is common practice to utilize…