Two-dimensional electron gas at a semiconductor-semiconductor interface

Ultrawide‐Bandgap Semiconductors: Research Opportunities and Challenges

“…These III-Vs, dominated by the III-P's and III-As's, have been of interest since the 1950s, when fundamental measurements showed not only that their electron mobilities were superior to those of Si and Ge, but also that their bandgaps were direct (implying stronger electron/hole/photon interactions, useful for optoelectronic devices), wider (implying higher breakdown voltages useful for electronic devices), and might be amenable to compositional modulation (or "engineerable" as in so-called "bandgap engineering"). [3] In electronics, the discovery [4] in the 1970s that the AlGaAs/ GaAs heterojunction could give rise to a two-dimensional electron gas (2DEG) was pivotal, enabling the first high-electronmobility transistors (HEMTs) in GaAs [5] and thin pseudomorphic strained InGaAs [6] channels. In the 1980s, these devices and their cousins, GaAs-and InGaAs-based heterojunction bipolar transistors (HBTs), quickly began setting records for unity-current-gain frequency (f T ) and output power above 10 GHz.…”

Free standing modulation doped core–shell GaAs/AlGaAs hetero‐nanowires

“…1 Introduction The invention of modulation or selective doping [1,2] in planar semiconductor heterostructures has led to an increase of the electron mobilities µ at low temperatures by orders of magnitude during the last three decades [3]. Two-dimensional electron systems (2DES) formed by this means in AlGaAs/GaAs heterojunctions have been the basis for many important discoveries in, both, fundamental physics and applied science such as the fractional quantum Hall effect [4] and the high electron mobility transistor, respectively.…”

Understanding the physics of a possible non-Abelian fractional quantum hall effect state.

“…At the present time, high quality two-dimensional electron gas (2DEG) can be routinely achieved in modulation doped AlGaAs/GaAs heterostructures [7]. Figure 1 shows a schematic of such a structure.…”