Spatially Resolved Photo-Response of a Carbon Nanotube/Si Photodetector

Photodetectors based on vertical multi-walled carbon nanotube (MWCNT) film-Si heterojunctions are realized by growing MWCNTs on n-type Si substrates with a top surface covered by Si3N4 layers. Spatially resolved photocurrent measurements reveal that higher photo detection is achieved in regions with thinner MWCNT film, where nearly 100% external quantum efficiency is achieved. Hence, we propose a simple method based on the use of scotch tape with which to tune the thickness and density of as-grown MWCNT film and enhance device photo-response.

Automated summary

Photodetectors based on vertical multi-walled carbon nanotube (MWCNT) film-Si heterojunctions are successfully achieved by growing MWCNTs on n-type Si substrates covered with Si3N4 layers. Spatially resolved photocurrent measurements demonstrate that higher photo detection is achieved in regions with thinner MWCNT film, resulting in nearly 100% external quantum efficiency. Therefore, a simple method utilizing scotch tape is proposed to tune the thickness and density of the as-grown MWCNT film, thereby enhancing the device photo-response.