Fabrication of silicon optical nanoantennas by ultrahigh vacuum STM lithography

The paper reports on experiments on the observation of scanning tunnel microscope (STM)-induced light emission (STM-LE) from bare silicon surfaces and modified with STM lithography. We produced nanoscale hillocks (nanokhobs) on a crystalline Si substrate, which can be considered as nanoantennas enhancing STM-LE effect. Our experiments show that the nanoknobes formed on the surface of the original substrate did not provide the achievement of the goal. However, in-situ deposition of a 10 nm thick additional layer of undoped Si resulted in the increase of STM-LE quantum efficiency by an order of magnitude in comparison with original substrate. This effect paves the way for the fabrication of nanoscale electrically-driven light sources required for hybrid optoelectronic chips.