Fig. 1. Schematic of VCSEL epitaxial structure

Fig. 2. Production process of oxide aperture for VCSEL based on (NH₄)₂S wet passivation

Fig. 3. SEM pictures of sample sidewalls under different oxidation process conditions. (a) Sample 1,traditional oxidation; (b) sample 2, oxidation after passivation

Fig. 4. Micrographs of sample oxide apertures

Fig. 5. Oxidation depth versus time

Fig. 6. P-I-V test curves of 940 nm VCSEL with oxide aperture size of 5 μm at room temperature (25 ℃)

Fig. 7. Measured spectra of VCSEL at room temperature (25 ℃). (a) Comparison of spectra of VCSEL under two process conditions when driving current is 1 mA; (b) spectrum of VCSEL before passivation whencurrent is 8I_th; (c) spectrum of VCSEL after passivation whencurrent is 8I_th