Study On Silver Nanowire Films As Vertical Cavity Surface Emitting Laser Current Spreading Layer

Vertical cavity surface emitting laser(Vertical-Cavity Surface-Emitting Laser, referred to as VCSELs) by virtue of its low threshold current, single longitudinal mode operation and the divergence angle of circular symmetric beam, small high modulation bandwidth and easy two-dimensional integration and monolithic low cost advantages, has broad application prospects in optical communication, optical computing, optical storage, optical display, laser printing and other fields, has been widely favored by researchers. However, for the vertical cavity surface emitting lasers due to the active region of thin, single light low gain, it is difficult to obtain in the small current, large output power, this need to increase the aperture. But for VCSEL, the carrier aggregation effect that is injected into the working current of the active region is just a channel through the edge of the annular region is very narrow and the carrier density distribution in the active region is not uniform, especially when the size of the device is large, intuitive performance for its lasing spot showed obvious ring and middle ring light intensity is very weak the phenomenon of.To improve the injection current of device is not uniform, the equivalent thermal resistance reducing device, simplify the production process and improve the output power of the design of a silver nanowire film as current spreading layer vertical cavity surface emitting semiconductor laser. The silver nanowire thin films spin coated on common ring electrode structure of VCSEL surface is designed and successfully fabricated VCSEL laser device is more uniform in the existing theoretical and experimental conditions. Comparative analysis of spin coated with Ag nanowires and VCSEL thin films of silver nano film VCSEL has no effect on laser current density distribution. The analysis results show that the spin distribution of silver nanowires film as current spreading layer vertical cavity surface emitting lasers than vertical cavity surface emitting no silver nanowire film of semiconductor laser is more conducive to the carrier, effectively avoid the aggregation effect of laser ring electrode injection caused by the carrier, and make the traditional structure in central almost no light has been fully utilized, increasing the effective area of light emitting device. The results show that, on the surface of VCSEL is laid with silver nanowire films can be improved to some extent, the quality of optical devices.The main contents of this paper are summarized as follows:1. Simulated DBR reflection spectrum, the influence factors of DBR reflection spectrum is analyzed in detail, and DBR resistance problems were calculated and analyzed; At the same time, analysis of oxide aperture and electrode size effects on VCSEL current density distribution.2. Through selective oxidation, photolithography, wet etching technology and alloypreparation technology of non silver nanowire thin film VCSEL devices at the same time for ordinary surface preparation of Ag NWs films and Ag NWs films as the research and development of current spreading layer VCSEL. By drop coating method and spin coating method on glass and PET substrates were prepared with different concentrations of silver nanowire films. Finally get the light transmittance of Nanowire Films in 95% when the resistance in 20 /sq and ITO a level of silver. And the use of spin coating was prepared with silver nanowires film as current spreading layer VCSEL.3. Analysis of the characteristics of laser vertical cavity surface emitting. On the surface without laying silver nanowire thin film VCSEL devices of L-I-V curve, spectrum and far-field divergence angle test. The results showed the same preparation condition because of silver nanowires with high transparency and low resistance, when the silver nanowires were spin coated onto the surface of VCSEL time, equivalent to increase the injection current area, can make the current injected into the active region is more uniform, thus weakening due to non-uniform current injection the light emitting device of the problem of uneven. Comparative analysis of two kinds of devices in the near field photograph and output light power, we can obviously find the surface spin coating device VCSEL silver nanowire light emitting more uniform DC current test under the maximum output power of 24.4m W surface without VCSEL device maximum power 23.4m W spin coated silver nanowires increased 4.3%, differential resistance from 23.95 down to 21.13. At the same time through the device and the far field spectral measurement the test results show that when the surface of the VCSEL device is laid with silver nanowire thin film devices, redshift rate decreased from 0.085nm/K to 0.077nm/K, the divergence angle of 21.6 °from the device decreased to 19.2 °.This fully demonstrates the effectiveness of silver nanowires as the current expansion. Show the spin coating preparation of Silver Nanowire Films as potential current spreading layer.