| In this thesis, we have focused the object on the AlGaAsSb/InGaAsSb multiple quantum-well (MQW) lasers and photodetectors operating at wavelength beyond 2m. The device physics, device process and device characteristic have been investigated, the main results are as followings:The band structure of 2m AlGaAsSb/InGaAsSb strained MQW have been calculated by a 6 bands kp model for valence subbands, a self-consistent solution is obtained by solving Schrodinger equation and Possion's equation simultaneously. Based on the results of band structure, we have studied the gain spectra of the 2m lasers, the effects of strain and width of the well have been systematically investigated, we have pointed out that the model gain of the lasers can be improved by increasing the compression strain or decreasing the width of the well layers. The active region of lasers have been designed and optimized.The optical confinement factor of waveguide layer have been calculated by using transfer matrix and effective refractive index method, the design of broaden waveguide have been optimized by considering the near and far field distributing, we have pointed out that 0.3 -0.5m is a proper width for 2m AlGaAsSb/InGaAsSb waveguide layer.The dark current and RoA have been investigated, during the calculation, the recombination mechanism such as Auger recombination, generation and recombination, surface recombination and tunneling recombination are taken into account. We found that the surface recombination velocity greatly influences the dark current and RoA, based on the theory result, we have pointed out that the performance of InGaAsSb PIN photodiodes can be improved if we employ passivation to the de ector surface.The chemical etch of GaSb based materials has been studied and the etching process have been optimized. A new modified neutralized (NH4)2S solution for antimonide have been proposed, the better passivation effect was obtained than traditional alkali solution.The key devices process such as low temperature PECVD Si3Nx and lit-off for GaSb-based devices have been investigated for the first lime. Based on the study of these single processes, we set up a completed process of the device fabrication.A grating exposure system have been developed and demonstrated for mid-infrared lasers for the first time in China. We have studied photoresist dilution, developing, controlling of period and duty cycle, a whole process of grating fabrication was set up. By using the system, we have fabricated gratings with different periods on different substrates and epilayer, which provides a grating technology for the fabrication of DFB lasers.2m AlGaAsSb/InGaAsSb lasers with both structures of planar stripe and ridge waveguide have been fabricated. Planar stripe lasers show room temperature pulsed emission at a highest temperature as 340K. The threshold current density is 1.8KA/cm2, a higher characteristic temperature of 90K is obtained in the range of 220K and 340K. The emission spectrum shows a multiple modes structure at 2.01 um. For ridge waveguide lasers,continues work at room temperature was realized. The laser can be operating in CW mode worked at 60癈 with a threshold current density of 557A/cm2 at room temperature. The series resistance of lasers is as low as 1.8, the characteristic temperature is 88K and the external differential efficiency is 32% at room temperature.A passivation treatment has been employed to the surface of InGaAsSb PIN photodiodes by (NH4)2S solution. The I-V tests shows that the reverse dark current was decreased and R0A was increased greatly. The optoelectronics characteristic of devices was also improved dramatically, after passivation treatment, the detectivity D increased from and the reponsivity increased from 37 V/W to 256V/W.Based on the investigation of bonds form in passivation process by XPS, a chemical and physical mechanism of the passivation and the degradation have been proposed and demonstrated for the first time. A way to suppress effectively the degradation of sulfur passivation have be...
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