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URN etd-0726116-174629 Statistics This thesis had been viewed 602 times. Download 62 times. Author Y-Hsin Chang Author's Email Address No Public. Department Electrical Engineering Year 2015 Semester 2 Degree Master Type of Document Master's Thesis Language English Page Count 54 Title Characteristics of Ga2O3/GaSe hetero-structure grown by molecular beam epitaxy Keyword MBE heterostructure Ga2O3 GaSe GaSe Ga2O3 heterostructure MBE Abstract Layered semicomductor GaSe is a candidate of ultra thin divice where exhibits a stable atomic-thin layer. In a layer of GaSe, gallium and selenium are bonded in the sequence of Se-Ga-Ga-Se with covelent and ionic bounds. Layer and layer of GaSe are boned by Van der Waals force. It is discovered that the physical properties of GaSe have changed when exposed in atmosphere over time. A thin, uncontrollable native oxide bonding on the surface. It leads us to propose a metal/oxide/semiconductor (MOS) structure. In this work, the growth and characterization of Ga2O3/GaSe hetero-structures grown on c-sapphire by plasma assisted molecular beam epitaxy.
Two methods were employed: firstly, we propose the oxygen replace the selenium by oxygen plasma surface treament. Reactive oxygen species are intended to secceed selenium and construct a thin gallium oxide on the surface of GaSe. It is noticed that the structure of GaSe was demaged and etched. GaSe layer was grown under lightly gallium-rich conditions. Native gallium is intended to be provided as a source for constructing Ga2O3. Various growth temperature : 300 oC, 450 oC, 500 oC, 550 oC, was test, to construct high-temperature growth oxide and lower-temperature growth selenium compound.
Raman spectra of gallium-rich GaSe and Ga2O3/GaSe show reliable shift at A11g, E12g mode. In photoluminescence (PL) spectrua, luminescence of gallium-rich GaSe was enhanced by constructing heterostructure. X-ray photoelectron spectroscopy (XPS) and Auger depth profile was used to confirm the existence of Ga2O3. At last, crystal structure of the heterostructure was discussed by transmmision electron microscopy (TEM). Heterostructure was obsurved with two different structure of GaSe epitaxy layers. The atomic arrangment of GaSe, which close to gallium oxide, is reconstructed.
Advisor Committee Chu-shou Yang - advisor
Chia-Hsing Wu - co-chair
Jiin-Jyh Shyu - co-chair
Tsung-Hui Tsai - co-chair
Files Date of Defense 2016-07-11 Date of Submission 2016-07-28