The formation of interfaces
between crystalline solids with disparate
electronic or structural properties poses numerous challenges, as well
as opportunities for investigation of basic scientific issues. Such
control the incorporation of dissimilar materials into a common device
structure, such as a chemical or radiation sensor or a
Development of these emerging
technologies is hampered by lack of
about both the formation and the resultant properties of these
structures. For example, interface compounds formed during growth may
exist in three-dimensional form, but their unknown properties can
the device behavior. The research in Professor Olmstead's group focuses
on understanding both the mechanisms of thin film growth and the unique
properties of the resultant heterostructures at the atomic level.
Her group also investigates similarities and differences between bulk
and nanoscale materials.
Monolayer control of materials growth
is obtained with molecular
epitaxy (MBE), where beams of molecules impinge on a crystalline
in ultra-high vacuum (UHV) at rates of about 1-100 molecular
Using a UHV chamber with combined facilities for MBE and materials
experiments probe the development of electronic, optical, and atomic
at the monolayer level. Variable temperature scanning probe
microscopy yields nanoscale measurements during the growth
process. Other electon, photon and atom spectroscopies give additional
information about the complex chemical and physical interactions which
govern heterointerface properties, as do measurements of magnetic and
Our primary instrumentation in the
basement of the physics building includes an Omicron nanostructure
analysis facility largely funded by the Murdock Charitable Trust, which
includes interconnected UHV chambers with variable temperature scanning
probe microscopy, xray photoemission spectroscopy, low energy electron
diffraction, ion scattering spectroscopy and molecular beam epitaxy
capabilities. We also have a PHI Versaprobe imaging xray
photoemission system (50 micron resolution), funded by the Micron
Foundation, as well as a pulsed laser deposition
system for combinatorial materials exploration (also funded by the
Micron Foundation). The Micron Foundation also supported a
small-spot xray diffraction system located in the Micron CME lab in
Roberts Hall. All this equipment is shared with other research
groups. We also use a number of national facilities -- the
Advanced Light Source, Advanced Photon Source, and Spring-8
synchrotrons, as well as the National Center for Electron Microscopy.
Intrinsic Vacancy Chalcogenides for Spintronic Applications
This project is a collaboration
with Prof. Fumio Ohuchi in Materials Science and Engineering.
This project seeks to create new, silicon-compatible magnetic
utilizing transition-metal doped semiconducting chalcogenides for
spintronic applications. This project focuses on heteroepitaxial
growth of TM-doped III-VI based semiconductors and on the inter-related
structural, electronic, and magnetic properties of this largely
unexplored class of materials. The research is aimed both at
developing technologically relevant
materials and at understanding the nanoscale mechanisms underlying
their novel properties. The research seeks to elucidate mechanisms of
III-VI thin film growth, as well as to understand origins of possible
magnetism in these materials, and to develop III-VI growth
materials characterization to the stage where these materials may be
utilized for spintronic applications.
Development of this new
generation of materials will require new, basic knowledge about the
interacting constraints that control their electronic, optical and
The primary goals of this project
to establish an experimental and theoretical framework based on
nanoscale heteroepitaxial growth processes to optimize structural,
electronic, magnetic and optical properties of III-VI heterostructures;
to exploit III-VI interface compounds to control semiconductor
to incorporate magnetic impurities into tetrahedral
chalcogenides to develop a new class of dilute magnetic semiconductors;
This research will advance
knowledge regarding nanoscale mechanisms for
magnetization in dilute magnetic semiconductors, doping and
compensation in intrinsic vacancy compounds, heteroepitaxial
stabilization of metastable crystal structures, and interface mixing
and charge localization at interfaces between strongly dissimilar
materials. By exploring the physics and materials science of novel
materials at the frontier of device applications, where observation of
quantum phenomena requires high materials quality and possibilities for
device applications are controlled by nanoscale physics, knowledge is
generated that is generally applicable to other systems.
This work has been funded by the
through grant DMR-0605601 (Summary
Phase Change Materials for Nanoelectronics
This project is a
collaborative effort with Prof. Fumio Ohuchi in Materials Science
and Engineering and Prof. Sam Fain in Physics. We also
collaborate with Ken Beck at Pacific Northwest National Laboratory
(Richland), John Smythe at Micron Industries (Boise), and Toyohiro
Chikyow, Garcia Villora and K. Shimamora at National Institute for
Materials Science (Tsukuba, Japan).
This research project utilizes
Combinatorial Materials Exploration to develop new phase-change
materials. The effort centered at UW focuses on intrinsic vacancy
III-VI materials, especially In2Se3 and Ga2O3.
In2Se3 is of interest for non-volatile resistive
memory, as it undergoes a resistivity
change of 105 between the crystalline and amorphous
phases. Ga2O3 is of interest both for its
transparent conductivity, and for the ability to tune that conductivity
through vacuum or oxygen annealing. Our research seeks to
understand the mechanisms for this
change, both in thin films and in confined nanostructures, as well as
to explore the role of stoichiometry, impurities and processing
conditions on this transition. In addition, we seek to develop
appropriate data protocols for combinatorial materials exploration as
part of a Materials World Network program.
The scientific and technological goals for this project are:
To develop a fundamental
framework for amorphous-crystalline stabilization and transition
relevant to future semiconductor device technologies;
To elaborate new CME designs
varying both composition and processing on single samples;
To establish a combinatorial
informatics protocol for data sharing among different institutions.
In addition to its scientific and
technical goals, the collaboration aims:
To establish an
international hub for vibrant collaborations through CME,
To facilitate information
exchange on technological materials;
To provide a new paradigm of
materials exploration as an educational program for both senior
undergraduate and graduate students.
Controlling the growth morphology and
phase segregation of Mn-doped Ga2Se3 on Si(001), Tracy C. Lovejoy, Esmeralda N. Yitamben,
Steven M. Heald, Fumio S. Ohuchi and Marjorie A. Olmstead, Physical
Review B 83 (2011)
Correlation between Morphology, Chemical
Environment and Ferromagnetism in the Intrinsic-Vacancy
Magnetic Semiconductor: Cr-doped Ga2Se3/Si(001),
Marjorie A. Olmstead, Physical Review B 83 (2001) 045203link to PRBpreprint
states in Ga2Se3 on
Si(001):As, Tracy C. Lovejoy, Esmeralda N. Yitamben, Taisuke
Ohta, Samuel C. Fain,
Jr., Fumio S. Ohuchi and Marjorie A. Olmstead, Physical Review B 81 (2010) 245313. Link to PRB.
Sputtering Induced Co0
Formation in X-ray Photoelectron Spectroscopy of Nanocrystalline ZnCoO
Spinodal Enrichment Models,
Olmstead, and Daniel R. Gamelin, Journal of Applied Physics 107 (2010) 103917. Link to JAP
MnSe Phase Segregation During
Heteroepitaxy of Mn Doped Ga2Se3 on Si(001),
Physics Letters 95
(2009) 241907. link
APL. DOI 10.1063/1.3273858 Article Copy
Surface morphology of Cr:Ga2Se3
heteroepitaxy on Si(001), Esmeralda N. Yitamben, Tracy C.
Lovejoy, Dennis F. Paul, John B. Callaghan, Fumio S. Ohuchi and
Marjorie A. Olmstead, Physical Review B 80 075314 (2009). Link to PRB.
Surface morphology and
electronic structure of bulk single crystal β-Ga2O3(100),
Zheng, Fumio S. Ohuchi and
Marjorie A. Olmstead, Applied Physics Letters 94 (2009) 081906. link to APL
Heteroepitaxial Growth of the
Intrinsic Vacancy Semiconductor Al2Se3 on
Structure and Morphology,
Olmstead, and Fumio S. Ohuchi,
Physical Review B 78, 075321
(2008). link to
B. doi:10.1103/PhysRevB.78.075321article copy
Laser and Electrical Current
Induced Phase Transformation of In2Se3:
Semiconductor Thin Film on Si(111), Chih-Yuan Lu, Patrick J.
Shamberger, Esmeralda N. Yitamben, Kenneth M. Beck, Alan G. Joly,
Marjorie A. Olmstead, and Fumio S. Ohuchi, Applied Physics A93, 93-98 (2008)article copyLink to
Applied Physics A. doi: 10.1007/s00339-008-4776-8
buffer layer for oxide heteroepitaxy on Si(001), Diedrich. A.
Schmidt, Taisuke Ohta, C.-Y. Lu, A.A. Bostwick, Qiuming Yu, E.
Rotenberg, F. S. Ohuchi and Marjorie A. Olmstead, Applied Physics Letters 88 181903 (2006). link to APL.
doi:10.1063/1.2199451 article copy
Perovskite termination influence
in oxide heteroepitaxy, Diedrich. A.
Schmidt, Taisuke Ohta, Qiuming Yu, and Marjorie A. Olmstead, Journal of Applied Physics 99 113521 (2006). link
JAP doi: 10.1063/1.2202197 Article
Contrast in scanning probe
microscopy images of ultra-thin insulator films, Andreas
Klust, Taisuke Ohta, Markus Bierkandt, Carsten Dieter, Qiuming
Yu, Joachim Wollschl¨ager, Fumio S. Ohuchi, and Marjorie A.
Olmstead, Applied Physics
Letters, 88 063107
link to APL. preprint
during the growth of ultra-thin insulator ﬁlms on semiconductors: from
interface formation to bulk-like CaF2/Si(111)
ﬁlms, Andreas Klust, Taisuke Ohta, Aaron A. Bostwick, Eli
Rotenberg, Qiuming Yu, Fumio S. Ohuchi, and Marjorie A. Olmstead, Physical Review B 72, 204336 (2005). link
Chemical passivity of III-VI
bilayer terminated Si(111), Jonathan A. Adams, Aaron A.
Bostwick, Fumio S. Ohuchi and Marjorie A. Olmstead, Applied Physics Letters 87, 171906/1-3 (2005).preprint; link
Intrinsic vacancy induced
nanoscale wire structure in heteroepitaxial Ga2Se3/Si(001),
Taisuke Ohta, D. A. Schmidt, Shuang Meng,
Andreas Klust, Aaron Bostwick, Qiuming Yu, Marjorie A. Olmstead, and
Fumio S. Ohuchi, Physical Review
Letters, 94, 116102 (2005) preprint; link
PRL Cover photo of March
Electronic structure of the
Si(111):GaSe van der Waals-like
surface termination, Reiner Rudolph, Christian Pettenkofer,
Aaron A. Bostwick, Jonathan A. Adams, Fumio S. Ohuchi, Marjorie A.
Andreas Klein and Wolfram Jaegermann, New
7, p 108 (2005). link to NJP;
Heterointerface formation of
aluminum selenide with silicon: Electronic and atomic structure of
Si(111):AlSe, Jonathan A. Adams, Aaron Bostwick, Taisuke Ohta,
Fumio S. Ohuchi, and Marjorie A. Olmstead, Physical Review B 71,
195308 (2005). preprint; link to PRB.
Atomic structures of defects at GaSe/Si(111) heterointerfaces
studied by scanning tunneling microscopy, Taisuke Ohta, Andreas
Klust, Jonathan A. Adams, Qiuming Yu, Marjorie A. Olmstead and
Fumio S. Ohuchi, Phys. Rev. B 69, 125322 (2004). link
Epitaxial growth of laminar crystalline silicon on CaF2,
(9), 1289-1291 (2000). pdf
link to APL
Diffusion of Ge below the Si(100) Surface: Theory and
Blas Uberuaga, M.A. Leskovar, A. P. Smith, H. Jonsson and M. A.
Physical Review Letters, 84(11), 2441-2444 (2000). pdf
filelink to PRL
Interaction of Se and GaSe with Si(111), S. Meng, B. R.
and M. A. Olmstead, Physical Review B 61(11), 7215-7218 (2000). pdf
filelink to PRB
Heteroepitaxy of Strongly Disparate Materials: From
Epitaxy in CaF2/Si(111), M.A. Olmstead, Chapter 5 of Thin
Systems, Amy W. K. Liu and Michael Santos,
(World Scientific, 1999). [pdf
version (12.5 MB)
Interaction of GaSe with GaAs(111): Formation of
large lattice mismatch, L. E. Rumaner, M.A. Olmstead and F. S.
Journal of Vacuum Science and Technology B, 16, 977-988 (1998) pdf
Molecular beam epitaxy and interface reactions of layered
on Sapphire(0001), S. Chegwidden, Z. R. Dai, M. A. Olmstead and F.
S. Ohuchi, Journal of Vacuum Science and Technology A, 16, 2376-80
Thin Film Growth of III-VI Compound Semiconductors, F.
and M.A. Olmstead, in Encyclopedia of Electrical and Electronics
J. G. Webster, editor (Wiley, 1999).
Altered Photoemission Satellites at CaF2 and SrF2-on-Si(111)
Interfaces, E. Rotenberg, J. D. Denlinger and M. A. Olmstead,
Review B53, 1584 (1996). pdf
filelink to PRB
Growth Kinetics of CaF2/Si(111) Heteroepitaxy: A
Photoelectron Diffraction Study, J.D. Denlinger, E.
U. Hessinger, M. Leskovar, and M.A. Olmstead, Physical Review, B51,
filelink to PRB
Role of Step and Terrace Nucleation in heteroepitaxial
Growth Kinetics of CaF2/Si(111), Uwe Hessinger, M. A.
M. A. Olmstead, Phys. Rev. Lett. 75, 2380 (1995) pdf
filelink to PRL
Layer-by-Layer Resolved Core Level Shifts in CaF2
on Si(111): Theory and Experiment, E. Rotenberg, J.D. Denlinger, M.
Leskovar, U. Hessinger, and M.A. Olmstead, Physical Review, B50, 11052
filelink to PRB
a Model Ionic/Covalent System: Transition from
Chemisorption to Epitaxy, G.C.L. Wong, D. Loretto, E.
M.A. Olmstead, and C.A. Lucas, Physical Review Rapid Communications,
5716 (1993). pdf
filelink to PRB
Surface core-level shifts in CaF2-on-Si(111)
films: Experiment and theory, Eli Rotenberg, J. D. Denlinger,
Uwe Hessinger, M. Leskovar, and Marjorie A. Olmstead, J. Vacuum Science
and Technology B 11, 1444-1448 (1993). link
Local Field Corrections to Surface and Interface Core-Level
Insulators, E. Rotenberg and M.A. Olmstead, Physical Review Rapid
B46, 12884 (1992). pdf
filelink to PRB
Atomic-size Effects on the Growth of SrF2 and
J. D. Denlinger, E. Rotenberg, M. A. Olmstead, J. R. Patel, and E.
Physical Review Rapid Communications B43, 7335 (1991). pdf
filelink to PRB
Mentoring Junior Faculty: Advice to Department Chairs,
A. Olmstead, Committee on the Status of Women Gazette. html
version pdf version
and Surface Defects in Ga2O3,
Zheng, E. G. Villora, K. Shimamura, H. Yoshikawa, Y.
Yamashita , S.
Ueda, K. Kobayashi, S. Dunham, F.S. Ohuchi, M.A. Olmstead.
Resistive Switching in Big Band Gap
E. C. Villora, S. Ueda, A. Pakhomov, M. A. Olmstead and
Ferromagnetism in a Silicon-Compatible Dilute Magnetic Semiconductor:
Lovejoy, A. Pakhomov, S.
Heald, F. S. Ohuchi and M. A. Olmstead.
Models of Spinodal
Decomposition in an Oxide Diluted
Magnetic Semiconductor, Zn1-xCoxO, Michael A. White,
Tracy C. Lovejoy, Stefan T. Ochsenbein, Marjorie A. Olmstead, and
Defect States in the Wide Gap
Yitamben, A. Pakhomov, F.S. Ohuchi, M.A. Olmstead, E.G.
K. Shimamura Y. Yamashita , H. Yoshikawa, S.
Pis, K. Kobayashi, and S. Vaithiyalingam.
“Experimental band dispersions
and surface morphology of the wide band gap oxide semiconductor
and without Mn Doping,” T. C. Lovejoy, J. Morales, E. N.
Yitamben, N. Shamir, S. Zheng, S. C. Fain, F. S. Ohuchi, M. A. Olmstead
“Room temperature ferromagnetism
and surface morphology in Cr-doped Ga2Se3
Films on Si(001),” E. N. Yitamben, T. C. Lovejoy, D. F. Paul,
J. B. Callaghan, S. C. Fain, F. S. Ohuchi and M. A. Olmstead
“Measuring Atomic Size Objects
on Electrically Insulating Surfaces in Ultrahigh Vacuum,” S.C.
FAIN, N. RUZYCKI, J. MORALES, T.C. LOVEJOY, E.N. YITAMBEN, M.A.
OLMSTEAD, F.S. OHUCHI, University of Washington
“Impact of Intrinsic
Vacancies on Phase Change and Epitaxial Growth of In2Se3 on Si(111),” C.Y. LU, E.N.
YITAMBEN, T.C. LOVEJOY, University of Washington, K.M. BECK, A.G. JOLY,
Pacific Northwest National Laboratory, M.A OLMSTEAD, F.S. OHUCHI,
University of Washington
“Intrinsic Vacancy Chalcogenides
as Dilute Magnetic Semiconductors: Theoretical Investigation of
“Heteroepitaxial Growth and
Electronic Structure of Mn:Ga2Se3 Thin Films on Si(100):As: Exploration of a
Candidate Dilute Magnetic Semiconductor,” T.C. LOVEJOY, E.N.
YITAMBEN, University of Washington, T. OHTA, Lawrence Berkeley National
Laboratory, F.S. OHUCHI, M.A. OLMSTEAD, University of Washington
“Investigation of Cr:Ga2Se3 as a Candidate Dilute Magnetic
Semiconductor for Silicon Based Applications,” E.N. YITAMBEN,
T.C. LOVEJOY, I.N. GATUNA, F.S. OHUCHI, M.A. OLMSTEAD, University of