Demonstration of a Field-Effect Three-Terminal Electronic Device with an Electron Mobility Exceeding 40 Million cm^2/(Vs)

TL;DR

This paper demonstrates a three-terminal field-effect device with an electron mobility exceeding 40 million cm^2/(Vs), achieved through innovative fabrication techniques that preserve high mobility and open new avenues in quantum transport research.

Contribution

The authors introduce a flip-chip fabrication method that maintains ultra-high electron mobility in three-terminal devices, surpassing previous records and enabling advanced quantum transport studies.

Findings

Achieved electron mobility over 40 million cm^2/(Vs)

Successful fabrication without mobility degradation

Doubles previous mobility record in field-effect devices

Abstract

We report the fabrication and operation of a source-drain-gate three-terminal field-effect electronic device with an electron mobility exceeding $40\times 10^6$ cm$^2$ / (Vs). Several devices were fabricated, with the highest achieved electron mobility obtained using a symmetrically-doped GaAs/AlGaAs quantum well forming a two-dimensional electron gas (2DEG) with a density of $1.47(1) \times 10^{11}$ cm$^{-2}$ and a pristine, pre-fabrication electron mobility of $44(2) \times 10^6$ cm$^2$/(\text{Vs}). To circumvent the well-known degradation of electron mobility during fabrication, devices were fabricated using a flip-chip technique where all lithographic processing steps were performed on a separate sapphire substrate. This method demonstrates the successful operation of various gate assembly designs on distinct 2DEGs without observable mobility degradation. This advance doubles the previous record for field-effect electronic device mobility and enables access to new regimes of quantum transport and applications that were previously unfathomable due to mobility limitations.