The low-speed spin-coating method was developed to prepare uniform and interconnected silver nanowires (AgNWs) film with the transmittance of 95% and sheet resistance of 20Ω/sq on glass, which was comparable to ITO. The fitting value of σdc/σop of 299.3 was attributed to the spin-coating process. Advantages of this solution-processed AgNW film on AlGaInP light-emitting diodes (LEDs) as transparent conductive layer were explored. The optical output power enhanced 100%, and the wavelength redshift decreased from 12 to 3 nm, which indicated the AgNW films prepared by low-speed spin-coating possessed attractive features for large-scale TCL applications in optoelectronic devices.

The 4.2% mismatch at the Si/Ge interface has a significant impact on Si/Ge photodetectors. However, few researchers have attempted to determine the major noise source or study the effects of the Si/Ge interface on the dark current, the responsivity and the 3-dB bandwidth of these devices. In this letter, we found that the dark current was dominated by generation-recombination processes that were enhanced by trap-assisted-tunneling around the interface below 220 K, with a characteristic tunneling energy of E00 =14 meV corresponding to an effective mass of m*=18m0. This behavior can be explained by the rise in the heavy-hole band caused by the compressive strain on the Ge layer. When the temperature increased above 240 K, Shockley-Read-Hall (SRH) recombination was clearly observed and believed to be dominant. The responsivity, the collection efficiency and the absorption efficiency were all extracted at 850 nm, 1310 nm and 1550 nm. The absorption coefficient around the interface was found to be lower than that of the bulk material. In addition, comparison of the measured 3-dB frequency (∼20.6 GHz –0.5V) with the theoretical value (∼29.37 GHz) indicated that defects have little effect on the bandwidth at high frequencies.

High-speed, high-efficiency silicon photodetectors play important roles in the optical communication links that are used increasingly in data centers to handle the increasing volumes of data traffic and higher bandwidths required as use of big data and cloud computing continues to grow exponentially. Monolithic integration of the optical components with signal processing electronics on a single silicon chip is of paramount importance in the drive to reduce costs and improve performance. Here we report grating-enhanced light absorption in a silicon photodiode. The absorption efficiency is determined theoretically to be as high as 77% at 850 nm for the optimal structure, which has a thin intrinsic absorption layer with a thickness of 220 nm. The fabricated devices demonstrate a high bandwidth of 11.3 GHz and improved radio-frequency output power of more than 14 dB, thus making them suitable for use in data center optical communications.

Silver nanowire (AgNW) film was proposed to apply on the surface of the vertical-cavity surface-emitting lasers (VCSELs) with large aperture in order to obtain a uniform current distribution in the active region and a better optical beam quality. Optimization of the AgNW film was carried out with the sheet resistance of 28.4 Ω/sq and the optical transmission of 94.8% at 850 nm. The performance of VCSELs with and without AgNW film was studied. When the AgNW film was applied to the surface of VCSELs, due to its better current spreading effect, the maximum output optical power increased from 23.4 mW to 24.4 mW, the lasing wavelength redshift decreased from 0.085 nm/mA to 0.077 nm/mA, the differential resistance decreased from 23.95 Ω to 21.13 Ω, and the far field pattern at 50 mA decreased from 21.6° to 19.2°. At the same time, the near field test results showed that the light in the aperture was more uniform, and the far field exhibited a better single peak characteristic. Various results showed that VCSELs with AgNW on the surface showed better beam quality.