Improving light extraction of InGaN-based light emitting diodes with a roughened p-GaN surface using CsCl nano-islands

Semiconductor Lighting Technology Research and Development Center, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China.
Optics Express (Impact Factor: 3.53). 01/2011; 19(2):1065-71. DOI: 10.1364/OE.19.001065
Source: PubMed

ABSTRACT InGaN-based light emitting diodes (LEDs) with a top nano-roughened p-GaN surface are fabricated using self-assembled CsCl nano-islands as etch masks. Following formation of hemispherical GaN nano-island arrays, electroluminescence (EL) spectra of roughened LEDs display an obvious redshift due to partial compression release in quantum wells through Inductively Coupled Plasma (ICP) etching. At a 350-mA current, the enhancement of light output power of LEDs subjected to ICP treatment with durations of 50, 150 and 250 sec compared with conventional LED have been determined to be 9.2, 70.6, and 42.3%, respectively. Additionally, the extraction enhancement factor can be further improved by increasing the size of CsCl nano-island. The economic and rapid method puts forward great potential for high performance lighting devices.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    Optics Express 10/2014; 22(S6):A1589. DOI:10.1364/OE.22.0A1589 · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The following paper presents a study on the performance of InGaN/GaN-based light-emitting diodes (LEDs) with a nano-roughened p-GaN surface, which were grown by metal-organic chemical vapor deposition. This nano-roughened p-GaN surface was obtained by using nitrogen (N-2) as cyclopentadienyl magnesium (Cp2Mg) carrier gas during the growth of p-GaN layer. Research results show that the surface roughness of p-GaN layer is influenced by the injection flow of N-2 and the injection time of N-2. Under the optimal process condition, the light output power of LED with a nano-roughened p-GaN surface is improved by 30.4 % compared with that of conventional LED with an injection current of 20 mA. Meanwhile, current-voltage curve shows that the electrical performance of this sample is similar to that of conventional LED. The improvement of light output power is mainly attributed to the higher light extraction efficiency when nano-roughened p-GaN surface is adopted.
    Journal of Materials Science Materials in Electronics 10/2014; 25(10):4200-4205. DOI:10.1007/s10854-014-2149-y · 1.97 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The p-electrode of blue light-emitting diodes (LED) chips has a low transmittance on the blue light spectrum. The blue light emitted from the quantum wells under the p-electrode will be severely absorbed by p-electrode, which cause a decrease in blue light extraction efficiency (LEE). In this study, we first designed a current blocking layer (CBL) structure with the blue light reflection through the simulation software. The simulation results show that this structure can effectively improve blue LEE, and then, this structure was verified by experiment. Electroluminescence measurement results show that LED with Metal-distributed Bragg reflector (M-DBR) CBL exhibited better optical performance than the LED with SiO2 CBL and DBR CBL. It was found that M-DBR CBL can effectively increase the blue light reflectivity and prevent the light absorption from the metal p-electrode to improve LED’ blue LEE.
    Applied Physics A 12/2014; 118(3). DOI:10.1007/s00339-014-8923-0 · 1.69 Impact Factor


Available from
Jun 2, 2014