Decoupling Through-Tip Illumination from Scanning in Nanoscale Photo-SECM

The use of scanning electrochemical microscopy (SECM) for nanoscale imaging of photoelectrochemical processes at semiconductor surfaces has recently been demonstrated. To illuminate a microscopic portion of the substrate surface facing the SECM probe, a glass-sealed, polished tip simultaneously served as a nanoelectrode and a light guide. One issue affecting nanoscale photo-SECM experiments is mechanical interactions of the rigid optical fiber with the tip motion controlled by the piezo-positioner. Here we report an improved experimental setup in which the tip is mechanically decoupled from the fiber and light is delivered to the back of the tip capillary using a complex lens system. The advantages of this approach are evident from the improved quality of the approach curves and photo-SECM images. The light intensity delivered from the optical fiber to the tip is not changed significantly by their decoupling.

Automated summary

The use of scanning electrochemical microscopy (SECM) for nanoscale imaging of photoelectrochemical processes at semiconductor surfaces has been demonstrated recently. An improved experimental setup was developed to decouple the tip from the optical fiber and deliver light to the back of the tip capillary using a complex lens system, resulting in improved quality of approach curves and photo-SECM images.