Structural and band alignment properties of Al2O3 on epitaxial Ge grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy

Authors

Mantu K. Hudait
Yizheng Zhu
Deepam Maurya
Shashank Priya
Prabir K. Patra
Anson W. K. Ma
Ashish Aphale
Isaac Macwan, Fairfield UniversityFollow

Document Type

Article

Publication Date

4-5-2013

Abstract

Structural and band alignment properties of atomic layer Al₂O₃ 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 Al₂O₃ film and the Ge epilayer. The extracted valence band offset, ΔEv, values of Al₂O₃ 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 Al₂O₃ 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.

Comments

© 2013 American Institute of Physics

A link to freely available content has been provided.

Publication Title

Journal of Applied Physics

Repository Citation

Hudait, Mantu K.; Zhu, Yizheng; Maurya, Deepam; Priya, Shashank; Patra, Prabir K.; Ma, Anson W. K.; Aphale, Ashish; and Macwan, Isaac, "Structural and band alignment properties of Al2O3 on epitaxial Ge grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy" (2013). Engineering Faculty Publications. 312.
https://digitalcommons.fairfield.edu/engineering-facultypubs/312

Published Citation

Hudait, M. K., Zhu, Y., Maurya, D., Priya, S., Patra, P. K., Ma, A. W. K., Aphale, A., Macwan, I. (2013). Structural and band alignment properties of Al2O3 on epitaxial Ge grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy. Journal of Applied Physics, 113(13). doi: 10.1063/1.4799367

DOI

10.1063/1.4799367

Peer Reviewed