skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Thermoelectric performance of Si{sub 0.8}Ge{sub 0.2}/Si heterostructures synthesized by MBE and sputtering

Abstract

The electronic properties of bulk materials are altered when they are incorporated into quantum wells. These wells may or may not impart beneficial electronic properties to an ensemble of such interfaces. Two-dimensional quantum wells (2D QWS) have been synthesized by alternating layers of Si and Si{sub 0.8}Ge{sub 0.2}. Such nanostructures are being investigated as a candidate thermoelectric material for high figures of merit ({ital Z}). The predicted enhancement is attributed to the confined motion of charge carriers in the 2D QW and can be translated into a large increase in conversion efficiency. This combination of materials is of interest since Si{sub 0.8}Ge{sub 0.2} is the preferred thermoelectric material for high temperature applications. Other heterostructures are also being investigated. Two techniques have been used to prepare these multilayer Si/Si{sub 0.8}Ge{sub 0.2} films, high-rate dual-magnetron sputtering and molecular beam epitaxy (MBE). Films have been deposited on single-crystal silicon and sapphire substrates. Substrate heating was used as a means of controlling film structure and electronic properties. Both types of films have been characterized with transmission electron microscopy (TEM) and selected area transmission electron diffraction. The thermoelectric properties of these films have also been determined over a broad range of temperature, extending from themore » boiling point of liquid helium to 1200 K. The performance of the MBE and sputtered films have been systematically compared. Efforts have been made to correct the electronic measurements of all thin films for the effects of their respective substrates. Preliminary thermoelectric measurements of these multilayer structures, especially those produced with MBE, lead us to believe that significant gains in the thermoelectric figure of merit ({ital Z}) may be possible with this approach. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.« less

Authors:
; ;  [1]; ; ; ;  [2];  [3];  [4]
  1. Hi-Z Technology (??)
  2. Lawrence Livermore National Laboratory (United States)
  3. Naval Research Laboratory (United States)
  4. University of California, Los Angeles (United States)
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
87097
Report Number(s):
CONF-940830-
Journal ID: APCPCS; ISSN 0094-243X; TRN: 95:017391
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 316; Journal Issue: 1; Conference: 13. international conference on thermoelectrics, Kansas City, MO (United States), 30 Aug - 1 Sep 1994; Other Information: PBD: 10 Aug 1994
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; SILICON ALLOYS; THERMOELECTRIC PROPERTIES; GERMANIUM ALLOYS; SILICON; HETEROJUNCTIONS; MOLECULAR BEAM EPITAXY; SPUTTERING; ELECTRIC CONDUCTIVITY; THERMAL CONDUCTIVITY; SEEBECK EFFECT; TEMPERATURE DEPENDENCE; STRAINS; ENERGY-LEVEL DENSITY

Citation Formats

Elsner, N B, Ghamaty, S, Norman, J H, Farmer, J C, Foreman, R J, Summers, L J, Olsen, M L, Thompson, P E, and Wang, K. Thermoelectric performance of Si{sub 0.8}Ge{sub 0.2}/Si heterostructures synthesized by MBE and sputtering. United States: N. p., 1994. Web. doi:10.1063/1.46848.
Elsner, N B, Ghamaty, S, Norman, J H, Farmer, J C, Foreman, R J, Summers, L J, Olsen, M L, Thompson, P E, & Wang, K. Thermoelectric performance of Si{sub 0.8}Ge{sub 0.2}/Si heterostructures synthesized by MBE and sputtering. United States. https://doi.org/10.1063/1.46848
Elsner, N B, Ghamaty, S, Norman, J H, Farmer, J C, Foreman, R J, Summers, L J, Olsen, M L, Thompson, P E, and Wang, K. Wed . "Thermoelectric performance of Si{sub 0.8}Ge{sub 0.2}/Si heterostructures synthesized by MBE and sputtering". United States. https://doi.org/10.1063/1.46848.
@article{osti_87097,
title = {Thermoelectric performance of Si{sub 0.8}Ge{sub 0.2}/Si heterostructures synthesized by MBE and sputtering},
author = {Elsner, N B and Ghamaty, S and Norman, J H and Farmer, J C and Foreman, R J and Summers, L J and Olsen, M L and Thompson, P E and Wang, K},
abstractNote = {The electronic properties of bulk materials are altered when they are incorporated into quantum wells. These wells may or may not impart beneficial electronic properties to an ensemble of such interfaces. Two-dimensional quantum wells (2D QWS) have been synthesized by alternating layers of Si and Si{sub 0.8}Ge{sub 0.2}. Such nanostructures are being investigated as a candidate thermoelectric material for high figures of merit ({ital Z}). The predicted enhancement is attributed to the confined motion of charge carriers in the 2D QW and can be translated into a large increase in conversion efficiency. This combination of materials is of interest since Si{sub 0.8}Ge{sub 0.2} is the preferred thermoelectric material for high temperature applications. Other heterostructures are also being investigated. Two techniques have been used to prepare these multilayer Si/Si{sub 0.8}Ge{sub 0.2} films, high-rate dual-magnetron sputtering and molecular beam epitaxy (MBE). Films have been deposited on single-crystal silicon and sapphire substrates. Substrate heating was used as a means of controlling film structure and electronic properties. Both types of films have been characterized with transmission electron microscopy (TEM) and selected area transmission electron diffraction. The thermoelectric properties of these films have also been determined over a broad range of temperature, extending from the boiling point of liquid helium to 1200 K. The performance of the MBE and sputtered films have been systematically compared. Efforts have been made to correct the electronic measurements of all thin films for the effects of their respective substrates. Preliminary thermoelectric measurements of these multilayer structures, especially those produced with MBE, lead us to believe that significant gains in the thermoelectric figure of merit ({ital Z}) may be possible with this approach. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.},
doi = {10.1063/1.46848},
url = {https://www.osti.gov/biblio/87097}, journal = {AIP Conference Proceedings},
number = 1,
volume = 316,
place = {United States},
year = {1994},
month = {8}
}