In this study, we report a novel monolithically integrated GaN-based light-emitting diode (LED) with metal-oxide-semiconductor field-effect transistor (MOSFET). Without additionally introducing complicated epitaxial structures for transistors, the MOSFET is directly fabricated on the exposed n-type GaN layer of the LED after dry etching, and serially connected to the LED through standard semiconductor-manufacturing technologies. Such monolithically integrated LED/MOSFET device is able to circumvent undesirable issues that might be faced by other kinds of integration schemes by growing a transistor on an LED or vice versa. For the performances of resulting device, our monolithically integrated LED/MOSFET device exhibits good characteristics in the modulation of gate voltage and good capability of driving injected current, which are essential for the important applications such as smart lighting, interconnection, and optical communication.
Articles you may be interested inEffect of indium surfactant on stress relaxation by V-defect formation in GaN epilayers grown by metalorganic chemical vapor deposition J. Appl. Phys. 108, 093511 (2010); 10.1063/1.3487955 Strain effects on In x Al 1 − x N crystalline quality grown on GaN templates by metalorganic chemical vapor deposition J. Appl. Phys. 107, 043515 (2010); 10.1063/1.3305397 Indium migration paths in V-defects of InAlN grown by metal-organic vapor phase epitaxy Appl. Phys. Lett. 95, 071905 (2009); 10.1063/1.3204454
Study of defects evolution in GaN layers grown by metal-organic chemical vapor depositionNear-lattice-matched and highly compressive-strained In x Al 1−x N epilayers were grown on GaN templates by metalorganic chemical vapor deposition. The V-defects associated with screw-component threading dislocations ͑TDs͒ were found in all the In x Al 1−x N layers. Their origin and evolution were investigated through near-lattice-matched In 0.173 Al 0.827 N layers with different thicknesses. Furthermore, small V-defects not associated with TDs were also found in In x Al 1−x N layers with high In composition ͑x = 0.231͒. Stacking mismatch boundaries induced by lattice relaxation in In x Al 1−x N epilayers under large strain is believed to be another mechanism forming V-defects.
Abstract-We investigate the mechanism responding for performance enhancement of gallium nitride (GaN)-based light-emitting diode (LED) grown on chemical wet-etching-patterned sapphire substrate (CWE-PSS) with V-Shaped pit features on the top surface. According to temperature-dependent photoluminescence (PL) measurement and the measured external quantum efficiency, the structure can simultaneously enhance both internal quantum efficiency and light extraction efficiency. Comparing to devices grown on planar sapphire substrate, the threading dislocation defects of LED grown on CWE-PSS are reduced from 1.28 10 9 cm 2 to 3.62 10 8 cm 2 , leading to a 12.5% enhancement in internal quantum efficiency. In terms of the theoretical computing of radiation patterns, the V-Shaped pits roughening surface can be thought of as a strong diffuser with paraboloidal autocorrelation function, increasing the escape probability of trapped photons and achieving a 20% enhancement in light extraction efficiency. Moreover, according to the measurement of optical diffraction power, CWE-PSS demonstrated superior guided light extraction efficiency than that of planar sapphire substrate, thus an extra 7.8% enhancement in light extraction efficiency was obtained. Therefore, comparing to the conventional LED, an overall 45% enhancement in integrated output power was achieved.
We report a chemical-wet-etching patterned-sapphire-substrate (CWE-PSS) that simultaneously enhances internal quantum efficiency and light extraction efficiency of gallium nitride based light-emitting-diode (LED). According to transmission electron microscopy (TEM) images, the threading dislocations penetrating into active region was dramatically reduced in the CWE-PSS structure compared to the planar sapphire substrate, i.e. enhancement of internal quantum efficiency. And according to the measurement of angular dependent diffraction power, CWE-PSS also serves as a diffraction grating which diffracts guided light into escaping cones, further improving light extraction efficiency of LED device.
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