High-Sensitivity Single-Walled Carbon Nanotube/Graphene/Al₂O₃/Ge Near-Infrared Photodetector

At present, combining low-dimensional nanomaterials with high-dimensional nanomaterials is an effective way to enhance the performance of photodetectors. Single-walled carbon nanotubes (SWCNTs) are 1-D materials with high mobility and infrared absorption ability, as well as suitable energy band structures for combining with bulk semiconductors, which can effectively improve the performance of near-infrared photodetectors. In this article, a near-infrared photodetector with SWCNTs/graphene/Al2O3/n-Ge structure is constructed. Utilizing the nature of SWCNTs, the device has a large improvement in the responsivity. The contact defects between graphene and Ge are reduced with the help of Al2O3. The device has a good optical response with a maximum responsivity of 515.4 mA/W at 1064 nm, a detection rate of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6.25 \times 10^{{10}}$ </tex-math></inline-formula> Jones, and a rise-fall time of 13.5 and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$36.5~\mu $ </tex-math></inline-formula>s, providing a new way for the application of SWCNTs in near-infrared photodetectors.