Leah Bergman DMR-1202532
Professor of Physics, University of Idaho
6.0
Figure 1. The bandgap
energy of MgZnO as a
function of Mg composition.
The shaded area is the phase
segregation region where
both phases of cubic and
hexagonal coexist. The
crystal structure and the
segregation region were
determined via selective
resonant Raman scattering
with supporting evidence
from XRD1. The inset to the
figure is an image of one of
our flexible samples.
5.5
5.0
4.5
4.0
3.5
3.0
0
Interests in New Collaborations: Fostering interaction with
researchers that grow MgxZn1-xO with high Mg composition via
pulsed laser deposition. Our alloys that are grown via a
sputtering technique have microcrystalline morphology. Of
interest is the exploration of the optical properties of epitaxial
alloys.
Applied Physics Letters 102, 191902 (2013). “Probing Embedded Structural
Inhomogeneities in MgZnO Alloys via Selective Resonant Raman Scattering”
Dinesh Thapa, Jesse Huso, Hui Che, Michelle Huso, John L. Morrison, Diana Gutierrez,
M. Grant Norton, and Leah Bergman
1
20
30
40
50
60
70
80
Mg (Atm. %)
1300
-1
Solid symbols: 3.8 eV
Open symbols: 5.1 eV
-1
1LO Wavenumber (cm )
Primary Broader Impact Activity: Disseminating lectures to
the general public on topics of materials science in consumer
technology.
10
720
1250
680
2LO
1200
640
1LO
1150
600
0
10
20
30
2LO Wavenumber (cm )
Bandgap Energy (eV)
Primary Research Interest: Realization of novel alloys with
tunable optical properties and light emissions in the blue to the
UV part of the spectrum. Two alloy systems are being
investigated: ZnS1-xOx , and MgxZn1-xO, with the objective of
achieving alloys with known solubility and material properties
that enable optical properties by design at energy ranges below
and above that of pure ZnO, respectively.
These two alloy systems can have bandgaps and light emissions
spanning the blue to the deep-UV part of the optical spectrum:
~ 2.5 eV- 6.5 eV.
40
50
60
70
80
1100
Mg (Atm. %)
Figure 2. The selective resonant Raman analysis. The laser
excitation energy, when in resonance with the bandgap of an
embedded structure, results in a Raman signal from that structure.
Thus using different laser energies (in our case 3.8 eV and 5.1
eV) enables the detection of the alloy inhomogeneitis and the
determination of the phase segregation region 1.