| Vertical cavity surface-emitting lasers (VCSEL) is a new type of semiconductorlasers. By comparing to conventional edge-emitting lasers, it has a low thresholdcurrent, high efficiency, low power consμmption, small divergence angle, easy toform arrays, easy to couple with fiber and integrate with optical components.Materials with InGaAsP/InP,AlGaInAs/InP of InP-based and GaInNAs/GaAs ofGaAs-based was used by the long wavelength VCSEL devices. But InP-basedmaterials was leak seriously with carrier, weak restrictions on electronic, carrierleakage limit of p-type material layer and DBR high resistance of the reflectors,thermal failure apparently caused, affecting the service life of the device. However,the material of GaInNAs just compensate for the shortcomings of the InP-basedmaterials. The GaInNAs material has a lot of advantages such as the thermal lowsensitivity, high characteristic temperature，high offset ratio and high rates ofmodulation signals. The growth of GaInNAs material is difficulty, because n-dopedinto the solution of the problem has not a good solution.This paper is aiming at the problem of the study on growth of GaInNAsmaterial, it studies the theory of VCSEL and simulation. The research contents ofthis paper are sμmmarized as follows:⑴The vertical cavity surface emitting laser structures were calculated andanalyzed. Analysis of the effect of film thickness, incident wavelength and incidentangle to the reflectivity of DBR mirrors; Analysis of the density of States, theelectronic energy levels of valence and conduction band on effects of quantμm wellgain; analysis the influence of the length of the resonant cavity, cavity surfacecoefficient, optical limiting factor on the threshold current. The theoretical analysisshows that the electronic state density increases and the level of electronics thegreater in difference is in proportion to gain; the length of the resonant cavityincreased and cavity surface reflection coefficient decreases will make the currentthreshold increasing. The device of VCSEL with increasing of threshold currentleads to high characteristics of temperature and reducing the life-span of the device.⑵The850nm and980nmVCSEL structure is simulated by PICS3D software.Analyzing the effects of different nμmber and different semiconductor materials onDBR reflectivity; analyzing a nμmber of different quantμm well on the reflectance; simulating the850nm AlInGaAs/AlGaAs VCSEL and980nm GaInAs/GaAsVCSEL with threshold current and voltage, output power, gain and the carrierconcentration, the nμmber of different quantμm well emission spectrμm and waveintensity. The simulation results show that the more pairs of DBR its reflectivity ishigher; reaching the same reflectivity using different materials required for the DBRpairs is not the same. The reflectivity of Al0.9Ga0.1As/Al0.1Ga0.9As reaching to99.5%requires24pairs, but for the GaAs/AlAs material requiring only22pairs. Thethreshold current of850nm for VCSEL is0.3mA, slope efficiency is0.75W/A, whenthe current is5mA, the output power is4.2mW; the threshold current of980nm forVCSEL is0.45mA, the slope efficiency is0.2W/A, when the the current is5mA,the output power is1.2mW.⑶Studying on the growth conditions of GaInNAs/GaAs strain quantμm wellwith MOCVD. Studying on the growth temperature, different N/(N+As) the effectof flow velocity, different N/As ratio on the effect of quality of the crystal film;annealing on GaInNAs quantμm well, studied the effect of annealing on theproperties of GaInNAs thin films, and optimize the annealing time and temperature.And we are using Philips PLM100PL spectrometer to test the property of growthsamples. |
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