Browsing by Author "Chuo, CC"

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Improvement of near-ultraviolet InGaN/GaN light-emitting diodes by inserting an in situ rough SiN(x) interlayer in n-GaN layers
(2003-10-27)
Tu, RC
;
Chuo, CC
;
Pan, SM
;
Fan, YM
;
Tsai, CE
Near-ultraviolet 400-nm InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with and without an in situ rough SiN(x) interlayer inserted into the n-GaN underlying layer were grown on c-face sapphire substrates by metalorganic vapor phase epitaxy. Inserting the SiN(x) interlayer into the n-GaN underlying layer slightly reduced leakage current induced by reducing the defect density. Additionally, an enhancement of light extraction for the LED with a SiN(x) interlayer is expected because of the increased intensity of light scattered on the SiN(x) nanomask, changing the directions of propagation of light. Consequently, the emission efficiency of an LED with an in situ rough SiN(x) interlayer doubles that without a SiN(x) interlayer. (C) 2003 American Institute of Physics.
Improvement of near-ultraviolet InGaN/GaN light-emitting diodes by inserting an in situ rough SiNx interlayer in n-GaN layers
(2003-10-27)
Tu, RC
;
Chuo, CC
;
Pan, SM
;
Fan, YM
;
Tsai, CE
Near-ultraviolet 400-nm InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with and without an in situ rough SiNx interlayer inserted into the n-GaN underlying layer were grown on c-face sapphire substrates by metalorganic vapor phase epitaxy. Inserting the SiNx interlayer into the n-GaN underlying layer slightly reduced leakage current induced by reducing the defect density. Additionally, an enhancement of light extraction for the LED with a SiNx interlayer is expected because of the increased intensity of light scattered on the SiNx nanomask, changing the directions of propagation of light. Consequently, the emission efficiency of an LED with an in situ rough SiNx interlayer doubles that without a SiNx interlayer. (C) 2003 American Institute of Physics.
Performance of AlGaN/GaN heterostrucrure FETs over temperatures
(2004)
Lee, CC
;
Shih, CF
;
Lee, CP
;
Tu, RC
;
Chuo, CC
In this article, a comparison on the device performance of the undoped and modulation-doped AlGaN/GaN HFETs over temperatures was presented. The results obtained indicated that the device structure has a significant influence on the device performance. The modulation-doped devices are superior to the undoped devices over the temperatures studied. The stability (the temperature dependence of device performance), however. is not as good as the undoped devices.
Quaternary AlInGaN multiple quantum well 368 nm light-emitting diode
(2006-01-25)
Wang, TC
;
Kuo, HC
;
Lee, ZH
;
Chuo, CC
;
Tsai, MY
We report high output power from AlInGaN multiple quantum well (MQW) ultraviolet light-emitting diodes. The high Al containing cladding layer, electron blocking layer and p-contact layer were chosen for transparency at 365 nm to reduce the internal absorption, reduce electron overflow and enhance output power. The UV output power was as high as 1.52 mW at 20 mA at 368 nm under room temperature CW operation. The maximum output power in CW operation is 11 mW at 170 mA. In this letter, we demonstrate a helpful and easy way to measure and calculate the junction temperature of AlInGaN UVLEDs. (c) 2005 Elsevier B.V. All rights reserved.
Temperature-dependent electron transport properties of AlGaN/GaN heterostructures
(2004-06-01)
Lee, CC
;
Shih, CF
;
Lee, CP
;
Tu, RC
;
Chuo, CC
In this article, a comparison on the temperature dependence of the electron transport properties of the undoped and modulation-doped AlGaN/GaN heterostructures is presented. The results obtained indicate that the device structure plays an important role in the temperature-dependent transport behavior of the devices. The undoped structure has a nearly constant 2DEG concentration over a wide temperature range. The modulation-doped structure has a temperature-dependent electron concentration. The increase in electron concentration in the modulation-doped structure at high temperatures is due to the thermal activation of Si donors in the AlGaN layer. In addition, the modulation-doped structure shows comparable electron mobility with the undoped structure at high temperatures, indicating that the modulation-doped structure would exhibit a better device performance at high temperatures.
Ultra-high-density InGaN quantum dots grown by metalorganic chemical vapor deposition
(2004-02-15)
Tu, RC
;
Tun, CJ
;
Chuo, CC
;
Lee, BC
;
Tsai, CE
This study examined how the duration of SiNx treatment on an underlying GaN layer affects the optical property, surface morphology and density of following InGaN quantum dots (QDs). InGaN QDs with extremely high density of near 3 x 10(11) cm(-2) exhibited strong photoluminescence (PL) emission at room temperature (RT). Increasing the duration of the SiN, treatment of the underlying GaN layer, the RT-PL peak of the following InGaN nano-islands and QDs was found to be red-shifted from the violet to the greenish region, and the spectrum was broadened. Additionally, the average height of InGaN nano-islands and QDs increased with the duration of SiNs treatment, explaining the redshift of the RT-PL peak.