Reducing disorder in Ge quantum wells by using thick SiGe barriers

• DOI: 10.1063/5.0242746
• Publication Date: 2024-11-26T16:00:42Z
• Authors: Davide Costa; Lucas E. A. Steho...; Yi Huang; Sara Martí-Sánchez; Davide Degli Esposti; Jordi Arbiol; Giordano Scappucci
• Keywords: 0301 basic medicine; Condensed Matter - Materials Science; 0303 health sciences; Condensed Matter - Mesoscale and Nanoscale Physics; Quantum dots; Hall effect; Materials Science (cond-mat.mtrl-sci); FOS: Physical sciences; Percolation theory; Field effect transistors; Quantum wells; Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Heterostructures; High mobility electron gas; Materials properties; Solid solid interfaces; Transmission electron microscopy

We investigate the disorder properties of two-dimensional hole gases in Ge/SiGe heterostructures grown on Ge wafers, using thick SiGe barriers to mitigate influence semiconductor–dielectric interface. Across several heterostructure field effect transistors, we measure an average maximum mobility (4.4±0.2)×106 cm2/Vs at a saturation density (1.72±0.03)×1011 cm−2, corresponding long mean free path (30±1)μm. The highest measured is 4.68×106 cm2/Vs. identify uniform background impurities and interface roughness as dominant scattering mechanisms limiting representative device, evaluate percolation-induced critical (4.5±0.1)×109 cm−2. This low-disorder heterostructure, according simulations, may support electrostatic confinement holes gate-defined quantum dots.