Jisung Park

• Doctor of Philosophy
• PostDoc Position at Cornell University

The LaInO3/BaSnO3 heterostructure has recently emerged as a promising platform for realizing 2D electron gas (2DEG) with unique transport properties, including excellent field‐effect at room temperature. However, there is a limit to improving its mobility due to intrinsic defects including the threading dislocations occurring during film growth. In...

Transparent oxide thin film transistors (TFTs) are an important ingredient of transparent electronics. Their fabrication at the back‐end‐of‐line (BEOL) opens the door to novel strategies to more closely integrate logic with memory for data‐intensive computing architectures that overcome the scaling challenges of today's integrated circuits. A recen...

The growing interest in the growth and study of thin films of low-dimensional metallic delafossites, with the general formula ABO2, is driven by their potential to exhibit electronic and magnetic characteristics that are not accessible in bulk systems. The layered structure of these compounds introduces unique surface states as well as electronic a...

We report a synthetic route to achieve high electron mobility at room temperature in epitaxial La:BaSnO3/SrZrO3 heterostructures prepared on several oxide substrates. Room-temperature mobilities of 157, 145, and 143 cm2 V−1 s−1 are achieved for heterostructures grown on DyScO3 (110), MgO (001), and TbScO3 (110) crystalline substrates, respectively....

We report a synthetic route to achieve high electron mobility at room temperature in epitaxial La:BaSnO$_3$/SrZrO$_3$ heterostructures prepared on several oxide substrates. Room-temperature mobilities of 157, 145, and 143 cm$^2$V$^{-1}$s$^{-1}$ are achieved for heterostructures grown on DyScO$_3$ (110), MgO (001), and TbScO$_3$ (110) crystalline su...

We observe a catalytic mechanism during the growth of III-O and IV-O materials by suboxide molecular-beam epitaxy (S-MBE). By supplying the molecular catalysts In2O and SnO we increase the growth rates of Ga2O3 and In2O3. This catalytic action is explained by a metastable adlayer A, which increases the reaction probability of the reactants Ga2O and...

This paper introduces a growth method-suboxide molecular-beam epitaxy (S-MBE)-which enables a drastic enhancement in the growth rates of Ga2O3 and related materials to over 1 μm h^−1 in an adsorption-controlled regime, combined with excellent crystallinity. Using a Ga + Ga2O3 mixture with an oxygen mole fraction of x(O) = 0.4 as an MBE source, we o...

Bandgap engineering is central to the design of heterojunction devices. For heterojunctions involving monolayer-thick materials like MoS2, the carrier concentration of the atomically thin film can vary significantly depending on the amount of charge transfer between MoS2 and the substrate. This makes substrates with a range of charge neutrality lev...

We demonstrate a-axis YBa2Cu3O7−x/PrBa2Cu3O7−x/YBa2Cu3O7−x trilayers grown on (100) LaAlO3 substrates with improved interface smoothness. The trilayers are synthesized by ozone-assisted molecular-beam epitaxy. The thickness of the PrBa2Cu3O7−x layer is held constant at 8 nm, and the thickness of the YBa2Cu3O7−x layers is varied from 24 nm to 100 nm...

This paper introduces a growth method---suboxide molecular-beam epitaxy (S-MBE)---which enables the growth of Ga2O3 and related materials at growth rates exceeding 1 micrometer per hours with excellent crystallinity in an adsorptioncontrolled regime. Using a Ga + Ga2O3 mixture with an oxygen mole fraction of x(O) = 0.4 as an MBE source, we overcome...

We demonstrate a-axis YBa2Cu3O7-x/PrBa2Cu3O7-x/YBa2Cu3O7-x trilayers grown on (100) LaAlO3 substrates with improved interface smoothness. The trilayers are synthesized by ozone-assisted molecular-beam epitaxy. The thickness of the PrBa2Cu3O7-x layer is held constant at 8 nm and the thickness of the YBa2Cu3O7-x layers is varied from 24 nm to 100 nm....

We report a fully transparent thin-film transistor utilizing a La-doped BaSnO3 channel layer that provides a drain current of 0.468 mA/μm and an on-off ratio of 1.5 × 10⁸. The La-doped BaSnO3 channel is grown on a 100–150 nm thick unintentionally doped BaSnO3 buffer layer on a (001) MgO substrate by molecular-beam epitaxy. Unpatterned channel layer...

Epitaxial La doped BaSnO3 films were grown in an adsorption controlled regime by molecular beam epitaxy, where the excess volatile SnOx desorbs from the film surface. A film grown on a (001) DyScO3 substrate exhibited a mobility of 183 cm^2 V^-1 s^-1 at room temperature and 400 cm^2 V^-1 s^-1 at 10 K, despite the high concentration (1.2x10^11 cm^-2...

We measured the photoconductivity of transparent semiconductor BaSnO3 and compared it with that of SrTiO3. Epitaxial BaSnO3 and SrTiO3films were grown on MgO substrates to exclude any contribution to photoconductivity from the substrate due to its large bandgap. In spite of the same perovskitestructure and similar bandgap sizes (3.1–3.2 eV), the ph...

We investigated the electronic transport properties of epitaxial SnO2−x thin films on r-plane sapphire substrates. The films were grown by pulsed laser deposition technique and its epitaxial growth direction was [101] and the in-plane alignment was of SnO2−x [010]// Al 2 O 3 [ 1 2 ̄ 10 ] . When the SnO2−x films were grown in the oxygen pre...

We demonstrate an all-perovskite transparent heterojunction field effect transistor made of two lattice-matched perovskite oxides: BaSnO3 and LaInO3. We have developed epitaxial LaInO3 as the gate oxide on top of BaSnO3, which were recently reported to possess high thermal stability and electron mobility when doped with La. We measured the dielectr...

We fabricated an n-type accumulation-mode field effect transistor based on BaSnO3 transparent perovskite semiconductor, taking advantage of its high mobility and oxygen stability. We used the conventional metal-insulator-semiconductor structures: (In,Sn)2O3 as the source, drain, and gate electrodes, Al2O3 as the gate insulator, and La-doped BaSnO3...