Browsing by Author "Li, Y. -H."

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Domain Matching Epitaxial Growth of High-Quality ZnO Film Using a Y(2)O(3) Buffer Layer on Si (111)
(2009-01-01)
Liu, W. -R.
;
Li, Y. -H.
;
Hsieh, W. F.
;
Hsu, C. -H.
;
Lee, W. C.
High-quality ZnO epitaxial films have been grown by pulsed-laser deposition on Si (111) substrates using a nanothick high-k oxide Y(2)O(3) buffer layer. Determined by X-ray diffraction and transmission electron microscopy, the epitaxial relationship between ZnO and Y(2)O(3) follows (0001)< 2 (1) over bar(1) over bar0 >(ZnO)parallel to(111)< 10 (1) over bar > Y(2)O(3). ZnO lattice aligns with the hexagonal O sublattice in Y(2)O(3) and the interfacial structure can be well described by domain matching epitaxy with 7 or 8 ZnO {11 (2) over bar0} planes matching 6 or 7 {4 (4) over bar0} planes Of Y(2)O(3) and lead to a significant reduction of residual strain. Superior optical properties were obtained even for ZnO films as thin as 0.21 mu m from photoluminescence results.
Domain Matching Epitaxial Growth of High-Quality ZnO Film Using a Y2O3 Buffer Layer on Si (111)
(2009-01-01)
Liu, W. -R.
;
Li, Y. -H.
;
Hsieh, W. F.
;
Hsu, C. -H.
;
Lee, W. C.
High-quality ZnO epitaxial films have been grown by pulsed-laser deposition on Si (111) substrates using a nanothick high-k oxide Y2O3 buffer layer. Determined by X-ray diffraction and transmission electron microscopy, the epitaxial relationship between ZnO and Y2O3 follows (0001)< 2 (1) over bar(1) over bar0 >(ZnO)parallel to(111)< 10 (1) over bar > Y2O3. ZnO lattice aligns with the hexagonal O sublattice in Y2O3 and the interfacial structure can be well described by domain matching epitaxy with 7 or 8 ZnO {11 (2) over bar0} planes matching 6 or 7 {4 (4) over bar0} planes Of Y2O3 and lead to a significant reduction of residual strain. Superior optical properties were obtained even for ZnO films as thin as 0.21 mu m from photoluminescence results.
Gain enhancement techniques for CMOS LNA and mixer
(2006-10-01)
Su, J. -Y.
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Meng, C. C.
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Li, Y. -H.
;
Tseng, S. -C.
;
Huang, G. -W.
Two major techniques for gain improvement of the CMOS low noise amplifier (LNA) and mixer are presented. First, the inductive interstage matching is applied to design a cascode amplifier for increasing the power transfer between the common source (CS) and common gate (CG) stages. Second, a super source follower (SSF) is utilized in a P-type micromixer for increasing the conversion gain of the mixer. A series of investigations are performed for demonstrating the feasibilities of the proposed techniques. The LNA and mixer designs based on the proposed techniques are realized using 0.35 im IP4M CMOS technology. Then their measured results are compared with those of a preliminary design, which fully integrates a conventional cascode amplifier and a P-type micromixer. The gain of the LNA is increased 2.1 dB and the noise figure is maintained at the same value of the preliminary design. On the other hand, the conversion gain of the super source follower (SSF) of the micromixer output is improved about 9.5 dB. Such improvements reveal great potential of the proposed design techniques on the gain enhancement for the LNA and mixer. Then, the measured results of the preliminary design show the return-loss of 25 dB, the isolation of better than 30 dB, and the conversion gain of 4.8 dB in the 2.4 GHz ISM hand. (C) 2006 Wiley Periodicals, Inc.
The influence of dislocations on optical and electrical properties of epitaxial ZnO on Si (111) using a gamma-Al2O3 buffer layer
(2012)
Liu, W. -R.
;
Lin, B. H.
;
Yang, S.
;
Kuo, C. C.
;
Li, Y. -H.
The structural, optical and electrical properties of the c-plane ZnO epitaxial films grown by pulsed laser deposition on a Si(111) substrate buffered with a thin layer of gamma-Al2O3 were investigated by X-ray diffraction, transmission electron microscopy, photoluminescence (PL) and Hall measurements. Detailed structural investigation showed that the dominant structural defects in the ZnO films are threading dislocations (TDs). Experimental results manifest the edge-and screw-type of TDs influence the optical and electric properties differently; the intensity ratio between the PL yellow-green band to near band edge emission and the carrier concentration are affected mainly by the edge TD, and the FWHM of the near band edge emission is dominantly influenced by the screw TD.