Byoungdeog Choi

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Current-Voltage (I-V) and Capacitance-Voltage (C-V) characteristics of crystalline silicon solar cells were obtained under UV exposure. The solar cell parameters degraded with increasing exposure time. For example, open-circuit voltage (V(oc)), short-circuit current (J(sc)), fill-factor (FF) and efficiency (eta) were degraded. In this study, solar cell did(More)
In this paper, we describe the fabrication of thin film transistors (TFTs) with amorphous indium-tin-zinc-oxide (ITZO) as the active material. A transparent ITZO channel layer was formed under an optimized oxygen partial pressure (OPP (%) = O2/(Ar + O2)) and subsequent annealing process. The electrical properties exhibited by this device include(More)
We investigated the carrier transfer and luminescence characteristics of organic light emitting diodes (OLEDs) with structure ITO/HAT-CN/NPB/Alq3/Al, ITO/HAT-CN/NPB/Alq3/Liq/Al, and ITO/HAT-CN/NPB/Alq3/LiF/A. The performance of the OLED device is improved by inserting an electron injection layer (EIL), which induces lowering of the electron injection(More)
Transparent conductive oxides (TCOs) have been widely used as transparent electrodes for opto-electronic devices, such as solar cells, flat-panel displays, and light-emitting diodes, because of their unique characteristics of high optical transmittance and low electrical resistivity. Among various TCO materials, zinc oxide based films have recently received(More)
This work proposes a sequence of tests for detecting refresh weak cells based on data retention time distribution in the main cell array of DRAMs and verify the feasibility of the proposed method through analysis of 30 nm design-rule DRAM cells with Recess Channel Array Transistor (RCAT) and Buried Channel Array Transistor (BCAT). Basic idea of the proposed(More)
In this study, pulse frequency and reverse bias voltage is modified in charge pumping and advanced technique is presented to extract oxide trap profile in hot carrier stressed thin gate oxide metal oxide semiconductor field effect transistors (MOSFETs). Carrier trapping-detrapping in a gate oxide was analyzed after hot carrier stress and the relationship(More)
Low temperature polycrystalline silicon (LTPS) thin-film transistors (TFTs) have a high carrier mobility that enables the design of small devices that offer large currents and fast switching speeds. However, the electrical characteristics of the conventional self-aligned polycrystalline silicon (poly-Si) TFTs are known to present several undesired effects,(More)
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