Study on influence of cavity length on the electrical properties of deep violet InGaN double quantum well lasers (original) (raw)
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Design and performance of 1.55 μm laser using InGaN
Physica Status Solidi (c), 2010
This paper describes the theoretical design and performance of a novel InGaN-based 1.55 μm quantum well laser. A careful analysis of the optical and modal gain, threshold behavior, optical output, and efficiency with cavity length has been carried out. The spectral range of the optical material gain is found to be narrow and modal gain varies sharply with changing the reflectivity of the partially transparent mirror. It is found that a very small voltage of 1.10 V is required to reach the threshold current. A very small threshold current of 5.1 mA is required to emit the light. The calculated values of threshold current and threshold voltage are lower than the reported values of the conventional 1.55 μm laser. An efficiency of around 59% is found for a cavity length of 300 μm keeping the reflectivity at 35% of one mirror and 100% of other. The above study indicates that the proposed InGaN-based 1.55 μm laser is very promising for the fabrication of future high performance laser (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
AIP Conference Proceedings, 2008
Quantum well width effect on threshold current density and optical performance of InGaN/GaN single quantum well (SQW) laser diode was determined and investigated. Various thickness (2-5nm) of InO.13GaO.87N wells and 12nm GaN barriers were selected as an active region for Fabry-Perot (FP) cavity waveguide edge emitting laser diode. The quantum confined Stark created a strong quantum well width dependence of threshold current density in the strained InGaN/GaN quantum well laser. Based on our simulation investigation, the exciton localization effect dominated the recombination emission in the thin quantum well structure; while the quantum confined stark effect (QCSE) dominated the recombination emission in the wide quantum well structure. Higher characteristic temperatures were obtained and significantly improved when the quantum well thickness was (2 to 3nm).
Investigation of the performance characteristics of 500 nm to 510 nm green InGaN MQWs laser diodes
The performance characteristics of green InGaN multi-quantum well laser diode structures emitting at 500 nm to 510 nm were investigated numerically. A threshold current of 87.2 mA corresponding to the threshold current density of 4.84 kA/cm 2 and a threshold voltage of 8.837 V were achieved for a basic structure emitting at 504.31 nm output emission wavelength. The effects of well numbers, well thickness, barrier thickness, and barrier doping on performance characteristics such as output power, threshold current, slope efficiency, and differential quantum efficiency were studied. The basic structure and material parameters used in the model were extracted based on the newest literatures and experimental works. Simulation results indicated that lowest threshold current, highest output power, differential quantum efficiency and slope efficiency are observed when the number of well layers is one and well thickness is between 3 and 4 nm. Significant changes in output power, threshold current, and slope efficiency were observed with the variations in barrier thickness and doping.
Performance characteristics of cw InGaN multiple-quantum-well laser diodes
MRS Proceedings, 2000
ABSTRACTThe performance characteristics are reported for continuous-wave (cw) InGaN multiple-quantum-well laser diodes grown on epitaxially laterally overgrown GaN on sapphire substrates by metalorganic chemical vapor deposition. Room-temperature cw threshold currents as low as 41mA with operating voltages of 6.0V were obtained. The emission wavelength was near 400 nm with output powers greater than 20 mW per facet. Under cw conditions laser oscillation was observed up to 90°C. A significant reduction in thermal resistance was observed for laser diodes transferred from sapphire onto Cu substrates by excimer laser lift-off, resulting in increased cw output power of more than 100mW.
Staggered InGaN quantum well diode lasers emitting at 500 nm
Proceedings of SPIE - The International Society for Optical Engineering, 2009
Staggered InGaN quantum wells (QWs) are analyzed as gain media for laser diodes to extend the lasing wavelength towards 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 like In-content InGaN QWs structures are investigated to enhance the optical gain for laser diodes emitting in the green regime.
Optimization of InGaN Laser Diodes Based on Numerical Simulations
Acta Physica Polonica A, 2016
Simulations of blue and green laser diodes with InGaN quantum wells are presented. In this study, a particular emphasis on efficiency and optical power of the structures was placed. Effect of the aluminum content in an electron blocking layer on the electron overflow and efficiency is discussed. Substantial decrease of efficiency of laser diodes is reported for low aluminum levels. It is also shown that polarization charges existing in AlInGaN heterostructures grown on GaN polar direction and low ionization degree of magnesium acceptors lead to high resistance of these devices. These effects hinder the carriers from reaching an active region and consequently they impose high operating voltages.
Applied Physics Letters, 2010
Carrier lifetime at room temperature ͑RT͒ was measured for blue-violet emitting InGaN multiquantum wells as a function of excitation intensity. The carrier lifetime of a p/n-doped waveguide sample ͑PNLD͒ was longer than those of undoped or n-doped waveguide samples. For PNLD, the long decay component became dominant at moderate excitation, in contrast to the others for which the fast decaying component remained dominant. The lifetime behavior of PNLD, in conjunction with its strong photoluminescence intensity, originates from the reduction of nonradiative centers. We conclude that the defect density is an important determinant of the RT performance of blue-violet laser diodes.
Characterization of InGaN/AlGaN multiple-quantum-well laser diodes
Physics and Simulation of Optoelectronic Devices VII, 1999
This paper discusses the design and characteristics of 111-nitride based multi-quantum well (MQW) laser diodes grown on a-as well as c-plane sapphire substrates by metal organic chemical vapor deposition (MOCVD). Threshold current densities as low as 4.8 kA/cm2 have been observed on devices with CAIBE etched mirrors and a SiO2ITiO2 high reflective coating on both facets. The lowest threshold currents obtained were around 55 mA (Uth= 9.5V) for 3.tm 300Mm ridge-waveguide laser diodes devices which allow room temperature pulsed operation up to 70% duty cycle (devices mounted p-side up). From cavity length studies the distributed loss in our structures was determined to be of the order of 35-45 cm1. At threshold this corresponds to a maximum modal gain of about I 10 cm1 or a material gain of about 2200 cm1.
Applied Physics B, 2009
The optical properties of InGaN multi-quantumwell laser diodes with different polarization-matched AlIn-GaN barrier layers have been investigated numerically by employing an advanced device simulation program. The use of quaternary polarization-matched AlInGaN barrier layers enhances the electron-hole wave function overlap due to the compensation of polarization charges between InGaN quantum well and AlInGaN barrier layer. According to the simulation results, it is found that, among the polarizationmatched quantum-well structures under study, lower threshold current and higher slope efficiency can be achieved simultaneously when the aluminum composition in AlInGaN barrier layers is about 10-15%. The optimal polarizationmatched InGaN/AlInGaN laser diode shows lower threshold current and higher slope efficiency compared to conventional InGaN/InGaN laser diodes.
Characteristics of InGaN-AlGaN multiple-quantum-well laser diodes
1998
Abstract We demonstrate room-temperature pulsed current-injected operation of InGaAlN heterostructure laser diodes with mirrors fabricated by chemically assisted ion beam etching. The multiple-quantum-well devices were grown by organometallic vapor phase epitaxy on c-face sapphire substrates. The emission wavelengths of the gain-guided laser diodes were in the range from 419 to 432 nm. The lowest threshold current density obtained was 20 kA/cm 2 with maximum output powers of 50 mW.