skip to main content

Title: Scattering mechanisms in shallow undoped Si/SiGe quantum wells

We report the magneto-transport study and scattering mechanism analysis of a series of increasingly shallow Si/SiGe quantum wells with depth ranging from ∼ 100 nm to ∼ 10 nm away from the heterostructure surface. The peak mobility increases with depth, suggesting that charge centers near the oxide/semiconductor interface are the dominant scattering source. The power-law exponent of the electron mobility versus density curve, μ ∝ n{sup α}, is extracted as a function of the depth of the Si quantum well. At intermediate densities, the power-law dependence is characterized by α ∼ 2.3. At the highest achievable densities in the quantum wells buried at intermediate depth, an exponent α ∼ 5 is observed. We propose and show by simulations that this increase in the mobility dependence on the density can be explained by a non-equilibrium model where trapped electrons smooth out the potential landscape seen by the two-dimensional electron gas.
Authors:
; ;  [1] ; ; ; ;  [2] ;  [3]
  1. Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
  2. Department of Electrical Engineering and Graduate Institute of Electronic Engineering, National Taiwan University, Taipei 10617, Taiwan, R.O.C. (China)
  3. (China)
Publication Date:
OSTI Identifier:
22492121
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 5; Journal Issue: 10; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 36 MATERIALS SCIENCE; DENSITY; DIAGRAMS; ELECTRON GAS; ELECTRON MOBILITY; EQUILIBRIUM; GERMANIUM SILICIDES; HETEROJUNCTIONS; INTERFACES; QUANTUM WELLS; SCATTERING; SEMICONDUCTOR MATERIALS; SILICON; SURFACES; TRAPPED ELECTRONS; TWO-DIMENSIONAL SYSTEMS