http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Electrical characterizations of Neutron-irradiated SiC Schottky diodes
Geunwoo Ko,김홍렬,Joona Bang,김지현 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.1
Neutrons with an average energy of 9.8±0.8MeV were irradiated onto silicon carbide Schottky diodes. After bombardment at a fluency of 2.75×1011 neutron/㎠, the Schottky barrier height, ideality factor, and the leakage currents remained unchanged. The electrical properties began to deteriorate after bombardment at a fluency of 5.5× 1011 neutron/㎠. In this study, we demonstrate that SiC SBD is robust under neutron irradiations and is well suited for space operations up to bombardments at a fluency of 2.75×1011 neutron/㎠.
Peak channel temperature of graphene-based transistors.
Ko, Geunwoo,Jung, Younghun,Kim, Jihyun American Scientific Publishers 2010 Journal of Nanoscience and Nanotechnology Vol.10 No.8
<P>In this study, graphene was mechanically deposited on SiO2/Si substrate, followed by ohmic metallization using electron-beam lithography. Finite element analysis was employed to characterize the operating temperature of graphene-based devices using the experimentally determined current-voltage data. The temperature of the hottest spot where the underlying SiO2 layer was 300 nm thick was elevated up to about 70 degrees C at a 10 mW dissipated power. However, the operating temperature dropped to about 50 degrees C when the 300 nm thick SiO2 layer was replaced with a 20 nm thick SiO2 layer. Thermal management is very critical in the reliability of graphene-based high speed electronic devices because the high operating temperature can degrade the device performance.</P>
Jaehui Ahn,Geunwoo Ko,김지현,Michael A. Mastro,Jennifer Hite,Charles R. Eddy Jr. 한국물리학회 2010 Current Applied Physics Vol.10 No.2
This paper demonstrates the manipulation of neutral dielectric wires with high aspect ratio by a pulsed electric field. Dielectrophoretic (DEP) force and torque were employed to align the randomly positioned GaN nano- and micro-wires. A simulation of the DEP force alignment process confirmed the experimentally observed dependence on alignment yield to frequency and bias of the electric field. Current–voltage measurements of the GaN micro-wires, aligned by DEP force and torque to pre-patterned metal contacts,confirms that the direct manipulation of micro-sized wire with an electric field oscillated at a frequency of 10 kHz–5 MHz.
Kim, Sung,Hwang, Sung Won,Kim, Min-Kook,Shin, Dong Yeol,Shin, Dong Hee,Kim, Chang Oh,Yang, Seung Bum,Park, Jae Hee,Hwang, Euyheon,Choi, Suk-Ho,Ko, Geunwoo,Sim, Sunghyun,Sone, Cheolsoo,Choi, Hyoung Joo American Chemical Society 2012 ACS NANO Vol.6 No.9
<P>For the application of graphene quantum dots (GQDs) to optoelectronic nanodevices, it is of critical importance to understand the mechanisms which result in novel phenomena of their light absorption/emission. Here, we present size-dependent shape/edge-state variations of GQDs and visible photoluminescence (PL) showing anomalous size dependences. With varying the average size (d(a)) of GQDs from 5 to 35 nm, the peak energy of the absorption spectra monotonically decreases, while that of the visible PL spectra unusually shows nonmonotonic behaviors having a minimum at d(a) = ~17 nm. The PL behaviors can be attributed to the novel feature of GQDs, that is, the circular-to-polygonal-shape and corresponding edge-state variations of GQDs at d(a) = ~17 nm as the GQD size increases, as demonstrated by high-resolution transmission electron microscopy.</P>