Terahertz biomedical imaging using a terahertz emitter based on InAs nanowires

We demonstrate the potential of using InAs nanowires (NWs) on Si(111) substrates for terahertz (THz) imaging in biomedical diagnostics. The cost-effectiveness and high precision of InAs NWs are discussed in comparison with those of InAs substrates. Using THz time-domain spectroscopy, the peak-to-peak current signals of catalyst-free InAs NWs and the substrate were measured at 3.37 nA and 1.61 nA, respectively. The THz amplitude of the InAs NWs increased by 47.7% compared to InAs wafers, with a fill factor of 0.034. At frequencies of up to 0.25 THz, the THz amplitude of InAs NWs was higher than that of bulk InAs. The resolution of THz images of a slice of pork belly and rat brain tumour tissue acquired using the InAs NWs was similar to that obtained with the InAs substrates. This suggests that InAs NW-based THz devices on Si substrates, which allow for large-area and cost-effective fabrication, could be useful for biomedical diagnostics.