Light matter interaction in WS$_{2}$ nanotube-graphene hybrid devices

We study the light matter interaction in WS$_{2}$ nanotube-graphene hybrid devices. Using scanning photocurrent microscopy we find that by engineering graphene electrodes for WS$_{2}$ nanotubes we can improve the collection of photogenerated carriers. We observe inhomogeneous spatial photocurrent response with an external quantum efficiency of $\sim 1\%$ at 0 V bias. We show that defects play an important role and can be utilized to enhance and tune photocarrier generation.