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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 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. Lastly, 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] ;  [1] ;  [2] ;  [2] ;  [2] ;  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  2. National Taiwan Univ., Taipei (Taiwan); National Nano Device Labs., Hsinchu (Taiwan)
Publication Date:
Report Number(s):
SAND-2015-8681J
Journal ID: ISSN 2158-3226; AAIDBI; 607423
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
AIP Advances
Additional Journal Information:
Journal Volume: 5; Journal Issue: 10; Journal ID: ISSN 2158-3226
Publisher:
American Institute of Physics (AIP)
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; quantum wells; electron gas; heterojunctions; surface charge; tunneling
OSTI Identifier:
1236235

Laroche, Dominique, Huang, S. -H., Nielsen, Erik, Chuang, Y., Li, J. -Y., Liu, C. W., and Lu, Tzu -Ming. Scattering mechanisms in shallow undoped Si/SiGe quantum wells. United States: N. p., Web. doi:10.1063/1.4933026.
Laroche, Dominique, Huang, S. -H., Nielsen, Erik, Chuang, Y., Li, J. -Y., Liu, C. W., & Lu, Tzu -Ming. Scattering mechanisms in shallow undoped Si/SiGe quantum wells. United States. doi:10.1063/1.4933026.
Laroche, Dominique, Huang, S. -H., Nielsen, Erik, Chuang, Y., Li, J. -Y., Liu, C. W., and Lu, Tzu -Ming. 2015. "Scattering mechanisms in shallow undoped Si/SiGe quantum wells". United States. doi:10.1063/1.4933026. https://www.osti.gov/servlets/purl/1236235.
@article{osti_1236235,
title = {Scattering mechanisms in shallow undoped Si/SiGe quantum wells},
author = {Laroche, Dominique and Huang, S. -H. and Nielsen, Erik and Chuang, Y. and Li, J. -Y. and Liu, C. W. and Lu, Tzu -Ming},
abstractNote = {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 ∝ nα, 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. Lastly, 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.},
doi = {10.1063/1.4933026},
journal = {AIP Advances},
number = 10,
volume = 5,
place = {United States},
year = {2015},
month = {10}
}