Design and characteristics of staggered InGaN quantum-well light-emitting diodes in the green spectral regime
نویسندگان
چکیده
Staggered InGaN quantum wells (QWs) are investigated both numerically and experimentally as improved active region for light-emitting diodes (LEDs) emitting at 520–525 nm. Based on a self-consistent six-band k.p method, band structures of both two-layer staggered InxGa12xN/InyGa12yN QW and three-layer staggered InyGa12yN/InxGa12xN/InyGa12yN QW structures are investigated as active region to enhance the spontaneous emission radiative recombination rate (Rsp) for LEDs emitting at 520–525 nm. Numerical analysis shows significant enhancement of Rsp for both two-layer and three-layer staggered InGaN QWs as compared to that of the conventional InzGa12zN QW. Significant reduction of the radiative carrier lifetime contributes to the enhancement of the radiative efficiency for both two-layer and three-layer staggered InGaN QW LEDs emitting at 520–525 nm. Three-layer staggered InGaN QW LEDs emitting at 520–525 nm was grown by metal-organic chemical vapour deposition (MOCVD) by employing graded-temperature profile. Power density-dependent cathodoluminescence (CL) measurements show the enhancement of peak luminescence by up to 3 times and integrated luminescence by 1.8–2.8 times for the three-layer staggered InGaN QW LED. Electroluminescence (EL) output power of the staggered InGaN QW LED exhibits 2.0–3.5 times enhancement as compared to that of the conventional InGaN QW LED. The experimental results show the good agreement with theory.
منابع مشابه
Approaches for high internal quantum efficiency green InGaN light-emitting diodes with large overlap quantum wells.
Optimization of internal quantum efficiency (IQE) for InGaN quantum wells (QWs) light-emitting diodes (LEDs) is investigated. Staggered InGaN QWs with large electron-hole wavefunction overlap and improved radiative recombination rate are investigated for nitride LEDs application. The effect of interface abruptness in staggered InGaN QWs on radiative recombination rate is studied. Studies show t...
متن کاملOptical gain characteristics of staggered InGaN quantum wells lasers
Staggered InGaN quantum wells QWs are analyzed as improved gain media for laser diodes LDs lasing at 440 and 500 nm. The calculation of band structure is based on a 6-band k ·p method taking into account the valence band mixing, strain effect, and spontaneous and piezoelectric polarizations as well as the carrier screening effect. Staggered InGaN QWs with two-layer and three-layer step-function...
متن کاملNanostructure engineering of staggered InGaN quantum wells light emitting diodes emitting at 420-510 nm
متن کامل
CORRIGENDUM: A novel wavelength-adjusting method in InGaN-based light-emitting diodes
The pursuit of high internal quantum efficiency (IQE) for green emission spectral regime is referred as "green gap" challenge. Now researchers place their hope on the InGaN-based materials to develop high-brightness green light-emitting diodes. However, IQE drops fast when emission wavelength of InGaN LED increases by changing growth temperature or well thickness. In this paper, a new wavelengt...
متن کاملImproving Blue InGaN Laser Diodes Performance with Waveguide Structure Engineering
To enhance lasers’ power and improve their performance, a model wasapplied for the waveguide design of 400 nm InGaN/InGaN semiconductor laser, whichis much easier to implement. The conventional and new laser structures weretheoretically investigated using simulation software PICS3D, which self-consistentlycombines 3D simulation of carrier transport, self-heating, and opt...
متن کامل