TY - JOUR
T1 - Structural and band alignment properties of Al2O3 on epitaxial Ge grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy
AU - Hudait, Mantu K.
AU - Zhu, Yizheng
AU - Maurya, Deepam
AU - Priya, Shashank
AU - Patra, Prabir K.
AU - Ma, Anson W. K.
AU - Aphale, Ashish
AU - Macwan, Isaac
PY - 2013/4/5
Y1 - 2013/4/5
N2 - Structural and band alignment properties of atomic layer Al 2 O 3 oxide film deposited on crystallographically oriented epitaxial Ge grown in-situ on (100), (110), and (111)A GaAs substrates using two separate molecular beam epitaxy chambers were investigated using cross-sectional transmission microscopy (TEM) and x-ray photoelectron spectroscopy (XPS). High-resolution triple axis x-ray measurement demonstrated pseudomorphic and high-quality Ge epitaxial layer on crystallographically oriented GaAs substrates. The cross-sectional TEM exhibited a sharp interface between the Ge epilayer and each orientation of the GaAs substrate as well as the Al 2 O 3 film and the Ge epilayer. The extracted valence band offset, ΔEv, values of Al 2 O 3 relative to (100), (110), and (111) Ge orientations using XPS measurement were 3.17 eV, 3.34 eV, and 3.10 eV, respectively. Using XPS data, variations in ΔEv related to the crystallographic orientation were ΔE V (110)Ge>ΔE V (100)Ge≥ΔE V (111)Ge and the conduction band offset, ΔE c , related to the crystallographic orientation was ΔE c (111)Ge>ΔE c (110)Ge>ΔE c (100)Ge using the measured ΔE v , bandgap of Al 2 O 3 in each orientation, and well-known Ge bandgap of 0.67 eV. These band offset parameters are important for future application of Ge-based p- and n-channel metal-oxide field-effect transistor design.
AB - Structural and band alignment properties of atomic layer Al 2 O 3 oxide film deposited on crystallographically oriented epitaxial Ge grown in-situ on (100), (110), and (111)A GaAs substrates using two separate molecular beam epitaxy chambers were investigated using cross-sectional transmission microscopy (TEM) and x-ray photoelectron spectroscopy (XPS). High-resolution triple axis x-ray measurement demonstrated pseudomorphic and high-quality Ge epitaxial layer on crystallographically oriented GaAs substrates. The cross-sectional TEM exhibited a sharp interface between the Ge epilayer and each orientation of the GaAs substrate as well as the Al 2 O 3 film and the Ge epilayer. The extracted valence band offset, ΔEv, values of Al 2 O 3 relative to (100), (110), and (111) Ge orientations using XPS measurement were 3.17 eV, 3.34 eV, and 3.10 eV, respectively. Using XPS data, variations in ΔEv related to the crystallographic orientation were ΔE V (110)Ge>ΔE V (100)Ge≥ΔE V (111)Ge and the conduction band offset, ΔE c , related to the crystallographic orientation was ΔE c (111)Ge>ΔE c (110)Ge>ΔE c (100)Ge using the measured ΔE v , bandgap of Al 2 O 3 in each orientation, and well-known Ge bandgap of 0.67 eV. These band offset parameters are important for future application of Ge-based p- and n-channel metal-oxide field-effect transistor design.
UR - https://digitalcommons.fairfield.edu/engineering-facultypubs/312
UR - https://vtechworks.lib.vt.edu/handle/10919/51973
U2 - 10.1063/1.4799367
DO - 10.1063/1.4799367
M3 - Article
VL - 113
JO - Journal of Applied Physics
JF - Journal of Applied Physics
ER -