The degradation process of Vertical-cavity Surface-emitting lasers with high speed and a central wavelength at 850 nm is investigated via constant-current accelerated aging experiments. Degradation of the photoelectric performances under different operating conditions are characterized by optical output power, and forward and reverse bias current–voltage. The 1/f noise characteristics and formation mechanism are discussed in terms of the experimental results of low frequency noise below threshold current. The main composition of low frequency noise before and after aging, the bias current dependence and the origin of the noise are analyzed emphatically. The correlation between the degradation suggests that the loss of photoelectric performance and the fluctuation of low frequency noise characteristic can be attributed to the contagion of defects towards the active region of Vertical-cavity Surface-emitting lasers. Furthermore, the results of failure analysis confirmed the conclusion that the contagion of defects occurred towards the active region of the samples after aging.

GaAs-based oxide-confined vertical-cavity surface-emitting lasers (VCSELs) exhibit relatively low resistance against reliability-related damage. In order to gain a deeper understanding of the degradation and failure mechanism in oxide-confined VCSELs caused by electrostatic discharge (ESD)-induced defect proliferation, we investigated the effects of ESD stress on the degradation of optical-electrical characteristics and the evolution of defects in VCSELs under human body model test condition. The degradation threshold values for forward and reverse ESD pulse amplitudes were estimated to be 200 V and -50 V, respectively. Notably, VCSELs demonstrated greater sensitivity to reverse bias ESD compared to forward bias ESD. Analysis of optical emission and microstructure provided evidence that the device failure is attributed to an increase in ESD current density, leading to the multiplication of dark line defects (DLDs) originating from the edge of the device's oxide aperture. The formation of defects occurred suddenly in discrete events within small regions, rather than progressing gradually and uniformly. These defects propagated and led to damage across the entire active region. We believe that our results would be meaningful for improving the reliability of VCSEL in the future.

The long-term reliability of the commercially available vertical-cavity surface-emitting laser (VCSEL) at 1310 nm wavelength is investigated. To do so, a high current accelerated life test is used to evaluate the 1310 nm VCSEL reliability. Variations of properties that depend on the operating condition are characterized by the light-current-voltage, leakage current and low-frequency noise. When the aging current is 6 mA, 8 mA and 10 mA, the maximum output power reduces by 5%, 6% and 15% of the initial value, respectively. It is demonstrated theoretically and experimentally that the leakage current increases and reverse bias breakdown voltage decreases after the accelerated current aging test. The current noise power spectral density increases after the device ages, and the noise increases with the augment of the electrical stress. When the bias current of VCSEL is below the threshold, the frequency index factor and noise amplitude gradually increase with the bias current increase. Further, lifetime fitting curves of the devices at an accelerating current of 6 mA, 8 mA and 10 mA are obtained, and the median lifetime of 67 years at the operating current is extrapolated.

The ZnO thin films were prepared on an ordinary glass substrate using an optimized Sol-gel Method. X-ray diffraction patterns indicated that the grain size increased with increasing annealing temperature. The surface morphology of the films was also analyzed by atomic force microscopy get the same result. The UV-Vis absorption spectra showed that the band edge absorption at the ZnO band edge was strong, and the band gap of the film annealed at 450 °C was 3.29eV.