Polarimetric Vis-NIR photodetector based on self-aligned single-walled carbon nanotubes

Abstract

As a quasi-one-dimensional material, individual single-walled carbon nanotubes are extensively studied due to their anisotropic electronic, thermal and optical properties. However, despite prior efforts to produce large-scale architectures of aligned nanotubes and related devices, macroscopic manifestations of such properties remain limited. In this work, large monodomain films of aligned single-walled carbon nanotubes (SWCNTs) have been prepared by self-assembly. Sodium dodecyl benzene sulfonate and sodium deoxycholate were simultaneously used as surfactant to disperse self-aligned SWCNTs and then carbon nanotubes films got a high degree of alignment with a maximum LDr of approximately 1.6. Furthermore, SWCNTs-Au heterojunctions photodetectors were fabricated and exhibited the enhanced intrinsic polarization-dependent photocurrent as well as anisotropic conductivities. To improve the device responsivity, hydrazine was used as N-doping material and the detector responsivity up to 292.5 mA/W was obtained with a broadband spectral response spanning the visible (405 nm) to the near-infrared (980 nm), which is much higher than former SWCNTs photodetector. This method presents a potential application of spontaneously aligned SWCNTs for efficient, low-cost, scalable Vis-IR detection with a built-in polarimetry.