Kyung Rok Kim

Human cytosolic aspartyl-tRNA synthetase (DRS) catalyzes the attachment of the amino acid aspartic acid to its cognate tRNA and it is a component of the multi-tRNA synthetase complex (MSC) which has been known to be involved in unexpected signaling pathways. Here, we report the crystal structure of DRS at a resolution of 2.25 Å. DRS is a homodimer with a dimer interface of 3750.5 Å(2) which comprises 16.6% of the monomeric surface area. Our structure reveals the C-terminal end of the N-helix whi

We report the experiments of a plasmonic terahertz (THz) wave detector based on silicon (Si) field-effect transistors (FETs) in the nonresonant sub-THz (0.2 THz) regime. To investigate the effects of the overdamped charge asymmetry on responsivity ( R V ), a FET structure with the asymmetric source and drain area under the gate has been proposed. R V as a function of gate voltage in Si FET-based detectors integrated with an antenna has been successfully enhanced by the asymmetry ratio (η a = W D

The N-Myc downstream-regulated gene (NDRG) family belongs to the α/β-hydrolase fold and is known to exert various physiologic functions in cell proliferation, differentiation, and hypoxia-induced cancer metabolism. In particular, NDRG3 is closely related to proliferation and migration of prostate cancer cells, and recent studies reported its implication in lactate-triggered hypoxia responses or tumorigenesis. However, the underlying mechanism for the functions of NDRG3 remains unclear. Here, we

Negative-differential transconductance characteristics at room temperature with a peak-to-valley ratio of about two were observed in 30-nm square-channel silicon-on-insulator nMOSFETs with degenerately doped bodies. High channel-doping concentration creates the degeneracy in the p-type body of the self-aligned SOI MOSFET and consequently, enables band-to-band tunneling between degenerate body and source-drain. I/sub DS/-V/sub DS/ curves in the negative drain bias region also show band-to-band tu

We suggest the optimum permittivity for a high-kappa/metal gate (HKMG) CMOS structure based on the trade-off characteristics between the fringing field induced barrier lowering (FIBL) and gate induced drain leakage (GIDL). By adopting the high-kappa gate dielectric, the GIDL from the band-to-band tunneling at the interface of gate and lightly doped drain (LDD) is suppressed with wide tunneling width owing to the enhanced fringing field, while the FIBL effects is degenerated as the previous repor

Novel single-electron transistors with sidewall depletion gates on a silicon-on-insulator nano-wire have been fabricated by the conventional very large-scale integration technologies. The fabricated SETs show the controllable characteristics, which can be estimated from the device geometry. The electrically induced quantum dot is well defined in the intended spot and the fabricated SETs show reliable single-dot characteristics eliminating unintentionally formed potential barriers in a silicon-on

Abstract We propose complement double-peak negative differential resistance (NDR) devices with ultrahigh peak-to-valley current ratio (PVCR) over 10 6 by combining tunnel diode with conventional CMOS and its compact five-state latch circuit by introducing standard ternary inverter (STI). At the “high”-state of STI, n-type NDR device (tunnel diode with nMOS) has 1st NDR characteristics with 1st peak and valley by band-to-band tunneling (BTBT) and trap-assisted tunneling (TAT), whereas p-type NDR

We propose a numerical band-to-band tunneling model that is suitable for forward-biased silicon tunnel diode simulation. In this model, the tunneling attenuation factor, which depends on the local electric field and effective tunnel mass, determines the tunneling rate and negative differential resistance characteristics of the tunnel diode. Simulation results with the reduced tunnel mass m <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rx</inf> *=

We report Coulomb oscillations based on band-to-band tunneling through a valence band in silicon metal-oxide-semiconductor field-effect transistors. Degenerately p+-doped channel and n+-doped source/drain enables band-to-band tunneling, which can play a major role in the transport between the channel and source/drain. The formation of tunnel barriers and a quantum dot in a single-electron transistor structure originates from two p+–n+ tunnel junctions and a p+-doped channel with mesoscopic dimen

We have previously reported the controllable complementary n- and p-type negative-differential transconductance (NDT) characteristics of a FIBTET (field-induced band-to-band tunneling effect transistor) on a degenerately doped SOI MOSFET. In this work, we investigate key parameters of device design and demonstrate negative-differential conductance (NDC) as well as NDT characteristics in FIBTETs, which have a structure totally compatible with SOI MOSFETs. the critical dose condition distinguishin

Single-electron transistors with a side gate structure were fabricated on SOI (silicon-on-insulator) substrate. The silicon channel in which electrons could be transported was defined by electron-beam lithography, and the channel was wrapped by two side gates which could control the electrically induced tunnel barrier. The electrical characteristics of the fabricated device were measured at 4.2 K. The measured characteristics showed a larger current oscillation period and amplitude than those es

Novel metal-oxide-semiconductor (MOS)-based single-electron transistors (MOSETs) using band-to-band tunneling mechanism have been fabricated by the conventional silicon-on-insulator (SOI) MOSFET technologies. The fabricated SETs have tunnel barriers and quantum-dot formed by an extremely small channel between two p + -n + tunnel junctions in the degenerately doped SOI MOSFET. Coulomb oscillation was observed in the subthreshold region at liquid nitrogen temperature and total capacitance of quant

In this work, we propose extended design window which is helpful to judge whether the plasma-wave transistor (PWT) operates as a resonant terahertz (THz) electromagnetic (EM) wave emitter. When metal-oxide-semiconductor field-effect transistor (MOSFET) is on strong inversion which is believed to be an operation regime of PWT THz emitter, Boltzmann statistics is no longer valid and degenerate Fermi-Dirac distribution should be considered. Based on degenerate carrier velocity model, we report the