Browsing by Author "Yang, Z. K."

Now showing 1 - 2 of 2

High-quality nanothick single-crystal Y(2)O(3) films epitaxially grown on Si (111): Growth and structural characteristics
(2008-05-01)
Lee, Y. J.
;
Lee, W. C.
;
Nieh, C. W.
;
Yang, Z. K.
;
Kortan, A. R.
High-quality single-crystal nanothick Y(2)O(3) films have been grown epitaxially on Si (111) despite a lattice mismatch of 2.4%. The films were electron beam evaporated from pure compacted powder Y(2)O(3) target in ultrahigh vacuum. Y(2)O(3) 3 nm thick exhibited a bright, sharp, streaky reconstructed (4x4) reflection high energy electron diffraction pattern. Structural studies carried out by x-ray diffraction with synchrotron radiation and high-resolution transmission electron microscopy show that the films have the cubic bixbyite phase with a remarkably uniform thickness and high structural perfection. Two Y(2)O(3) domains of B-type Y(2)O(3) [2 (1) over bar(1) over bar]parallel to Si[11 (2) over bar] and A-type Y(2)O(3) [2 (1) over bar(1) over bar]parallel to Si[2 (1) over bar(1) over bar] coexist in the initial film growth with B type predominating over A type in thicker films as studied using x-ray diffraction. The narrow full width at half maximum of 0.014 degrees in the omega-rocking curve is the characteristic of excellent crystalline films. High-resolution transmission electron microscopy and fast Fourier transform analysis show atomically sharp interface and strain relaxation in thicker films. (C) 2008 American Vacuum Society.
Structure of HfO2 films epitaxially grown on GaAs(001)
(2006-09-18)
Hsu, C. -H.
;
Chang, P.
;
Lee, W. C.
;
Yang, Z. K.
;
Lee, Y. J.
High-quality HfO2 films of technologically important thickness ranging from 1.8 to 17 nm have been grown epitaxially on GaAs (001) by molecular beam epitaxy. Thorough structural and morphological investigations were carried out by x-ray scattering and high-resolution transmission electron microscopy. The films exhibit an atomically sharp interface with the substrate and are of a monoclinic phase with predominant (001)-plane epitaxy between the HfO2 films and GaAs, in spite of a large lattice mismatch of > 8.5%.