Browsing by Author "Tsai, MN"

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Short-diode like diffusion capacitance of organic light emission devices
(2006-03-01)
Tsai, MN
;
Chang, TC
;
Liu, PT
;
Ko, CW
;
Chen, CJ
A prototypical organic light-emitting diode (OLED), anode/organic layers/cathode, is investigated via bias-dependent capacitance measurement of two-layer (HTL/ETL) and four-layer (HIL/HTL/EML/ETL) structure at low frequency. As applied voltage was larger than the built-in voltage, the capacitance is augmented by diffusion capacitance with increasing the forward bias voltage. In contrast, the capacitance dropped quickly. It is possibly due to the voltage drop in the bulk and conductivity modulation occurred by high carrier concentration for much higher forward biases, eventually showing negative for two-layer OLEDs. We infer that the phenomena were resulted from the extremely thin OLED structure, just like short p-n semiconductor diodes. This diffusion capacitance exhibiting like short-diode behavior also can be measured in C-V curves of single-layer structure OLED. (c) 2005 Elsevier B.V. All rights reserved.
Single-mode 1.27-mu m InGaAs : Sb-GaAs-GaAsP quantum well vertical cavity surface emitting lasers
(2005-01-01)
Kuo, HC
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Chang, YH
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Chang, YA
;
Lai, FI
;
Chu, JT
The 1.27-mum InGaAs:Sb-GaAs-GaAsP vertical cavity surface emitting lasers (VCSELs) were grown by metalorganic chemical vapor deposition and exhibited excellent performance and temperature stability. The threshold current varies from 1.8 to 1.1 mA and the slope efficiency falls less than similar to35% from 0.17 to 0.11 mW/mA as the temperature is raised from room temperature to 75 degreesC. The VCSELs continuously operate up to 105 degreesC with a slope efficiency of 0.023 mW/mA. With a bias current of only 5 mA, the 3-dB modulation frequency response was measured to be 8.36 GHz, which is appropriate for 10-Gb/s operation. The maximal bandwidth is estimated to be 10.7 GHz(1/2) with modulation current efficiency factor of similar to5.25 GHz/(mA)(1/2). These VCSELs also demonstrate high-speed modulation up to 10 Gb/s from 25degreesC to 70degreesC. We also accumulated life test data up to 1000 h at 70degreesC/10 mA.
Temperature effects of n-MOSFET devices with uniaxial mechanical strains
(2006)
Tsai, MN
;
Chang, TC
;
Liu, PT
;
Cheng, O
;
Huang, CT
This work presents a means of causing mechanical uniaxial stress in n-type metal-oxide-semiconductor field-effect transistors (MOSFETs). The proposed method provided a valuable reference for research into both strained-Si and the temperature effect. In this article, tensile stress is applied parallel or perpendicular to the channel direction at room and high temperature. The shift in the energy levels of strained silicon depends on the direction of uniaxial strain, and changes the average in-plane transport mass. (c) 2006 The Electrochemical Society.