| The rapid development of network and optical communication technology require optoelectronic devices of next generation,which makes the research of long-wavelength (1.3μm and 1.55μm)vertical-cavity surface-emitting laser(VCSEL)to be widely focused. We have made a series of investigation of some key technology of long-wavelength VCSEL.Main innovatory results are included in the thesis;Complete processing procedure of VCSEL device has been developed,which includes mesa etching,surface passivation,fabrication of electrode patterns,ohmic contacts,optical films and so on.Optimized mesa units are accomplished by the etchant of HBr;HNO3;H2O, and the lowest specific contact resistance between p-InGaAsP and Ti-Au reaches 6.49×10-5Ω·cm2.1.3μm VCSEL device has been fabricated.The stop band and cavity mode of the VCSEL structure have been analyzed by measured reflectivity spectrum and transfer matrix method simulation.The optoelectronic characterizations of VCSEL device have been tested,whose emission wavelength is 1.3μm and FWHM is 5.8nm at room temperature.And the shifts of gain peak position and cavity mode position at different temperatures have been analyzed.In order to resolve the problem of p-type materials in VCSEL having larger resistance and worse heat dissipation,we have developedδdoped AlInAs-InP tunnel junction structure,which can replace p-type materials with n-type materials.Electrical properties of the tunnel junctions have been calculated and it is found that AlInAs-InP hetero-tunnel junction is superior to AlInAs or InP homo-tunnel junction.AlInAs-InP tunnel junction has been fabricated with specific contact resistivity of about 10-4Ω·cm2.The tunnel junction has been applied in 1.3μm VCSEL structure.The VCSEL structure demonstrates lower threshold voltage,and the gain peak position measured from electroluminescence spectrum has not been changed.The requirement of electrical confined aperture in VCSEL urges us into investigating lateral wet-etching and ion implantation.Electrical and optical characterizations of InP and 1.3μm surface-emitting laser structure influenced by H+ implantation are mainly investigated.The InP material surface is damaged after ion implantation,and is recovered after thermal annealing above 300℃.The resistance of the layer formed by ion implantation is as high as 104 times of that of InP bulk material.Then the 1.3μm surface-emitting laser structure which adopts the ion implantation technology is fabricated. It is found that the optimized thermal annealing temperature is 450℃and electroluminescence spectra intensity are enhanced after high-temperature thermal annealing.Tunable long-wavelength VCSEL that will be widely used in optical WDM systems has been primarily studied.Tuning deflection and tuning spectrum of the tunable long-wavelength VCSEL based on InP/air-gap have been theoretically analyzed. Fabrication of InP/air-gap structure by using lateral etching technology with different etchants is investigated.Etching rates,anisotropy and surface roughness are also analyzed. Then the surface stress profiling of the InP/air-gap structure has been carried out by micro-Raman measurements,which proves good reliability of our fabrication process.Besides above,the study about optical properties of p-type GaAs in far-infrared region has been accomplished during this period.
|
PDF Full Text Request