Browsing by Author "Chen, Yu-Xun"

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A gate-free monolayer WSe2 pn diode
(2018-08-07)
Chen, Jhih-Wei
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Lo, Shun-Tsung
;
Ho, Sheng-Chin
;
Wong, Sheng-Shong
;
Vu, Thi-Hai-Yen
Interest in bringing p- and n-type monolayer semiconducting transition metal dichalcogenides (TMD) into contact to form rectifying pn diode has thrived since it is crucial to control the electrical properties in two-dimensional (2D) electronic and optoelectronic devices. Usually this involves vertically stacking different TMDs with pn heterojunction or, laterally manipulating carrier density by gate biasing. Here, by utilizing a locally reversed ferroelectric polarization, we laterally manipulate the carrier density and created a WSe2 pn homojunction on the supporting ferroelectric BiFeO3 substrate. This non-volatile WSe2 pn homojunction is demonstrated with optical and scanning probe methods and scanning photoelectron microspectroscopy. A homo-interface is a direct manifestation of our WSe2 pn diode, which can be quantitatively understood as a clear rectifying behavior. The non-volatile confinement of carriers and associated gate-free pn homojunction can be an addition to the 2D electron-photon toolbox and pave the way to develop laterally 2D electronics and photonics.
Effects of pillar size modulation on the magneto-structural coupling in self-assembled BiFeO3-CoFe2O4 heteroepitaxy
(2020-01-21)
Amrillah, Tahta
;
Chen, Yu-Xun
;
My Ngoc Duong
;
Abdussalam, Wildan
;
Simanjuntak, Firman Mangasa
The magneto-structural coupling of BiFeO3 (BFO)-CoFe2O4 (CFO)/LaAlO3 (LAO) heteroepitaxy with various lateral sizes of CFO pillars embedded in a BFO matrix was investigated. A structural phase transformation of the BFO matrix was observed when the pillar size of CFO was increased to exceed 200 nm. Such structural transformation led to modification of magneto-elastic coupling behavior and magnetic anisotropy in the BFO-CFO/LAO system. The flexibility of tuning the pillar size of CFO, and hence, the strain and interfacial effect on the multiferroic system have significant application implications in these functional oxide nanocomposites.