Material Epitaxy And Process Design Of 1.3-?m InAs/GaAs Quantum Dot Lasers

With the development of optical fiber communication and high-speed informatization,as the light source of optical fiber communication,the performance requirements of semiconductor lasers are getting higher and higher.Because of the unique material properties of semiconductor quantum dots,domestic and foreign attention has been focused on the development and industrialization of high-performance quantum dot lasers.At present,most of the communication band lasers are mainly InP-based lasers,but these lasers have many disadvantages and are difficult to be used as low-cost high-speed transmission light sources.The 1.3-?m InAs/GaAs quantum dot lasers exhibit the advantages of low threshold current density,high differential gain,high temperature stability,high modulation speed,and low frequency ripple effect due to the three-dimensional quantum confinement effect,becoming an excellent choice of light source for optical communications.High-density quantum dots are the decisive factor in improving quantum dot lasers,however the traditional S-K growth mode increases the density of quantum dots when changing certain growth conditions,and also increases the dislocation density in the quantum dot system.In this paper,a 1.3-?m In As/GaAs QD laser with low threshold current density,low power consumption,and a high characteristic temperature is taken as a target to carry out relevant material growth,device fabrication and performance analysis and testing research.We achieved some important and innovative results as follows:Based on the S-K growth mode,the growth temperature,V-III ratio,InAs deposition,and thickness and Indium composition of the capping layer InGaAs were optimized,and the AFM and PL spectra were used to characterize the 1.3 um InAs/GaAs QDs.The optimum growth temperature of In As/GaAs quantum dots is 520?;the optimal V-III ratio is 25 times;the Arsenic pressure is 1.4E-8 Torr;the deposition amount of InAs is 2.5 ML,which is monitored by RHEED 1.3 times,the deposition rate of InAs is 0.025 ML/s;the growth thickness of the cap layer InGaAs is 5 nm,and the In composition is 0.15;Single-layer high-temperature annealing was used to eliminate the double-mode system in the quantum dots,and the optimal annealing temperature was 680?.The density of InAs quantum dots grown in this growth system is 3.2×10¹⁰?88?^-2,and the center wavelength of photoluminescence is 1308 nm.Beryllium doping in the active region of 1.3?m InAs/GaAs quantum dot laser was epitaxially grown by?modulation doping.The doping position was changed and the doping of 5 nm GaAs material under the quantum dot with fewer material lattice defects was selected.A wide 1.3?m InAs/GaAs QD laser with a cavity length of 2 mm and a ridge width of100?m was fabricated.The lasing wavelength is 1300 nm,the threshold current density J_thh is 110 A/cm²,and the single-layer threshold current density was as low as 20 A/cm².The power is up to 1008 mW.The device can achieve a wide stable operation,and the highest characteristic temperature T₀ reaches 405 K.Continuous lasing can be stable at a high temperature of even 80? with an output power of 25 mW.