Nanoscale imaging and spectroscopy of charge carrier distribution in doped Si nanowires with terahertz and mid infrared near-field nanoscopy

We perform terahertz (THz) and mid infrared nanoscopy to probe and quantify charge carriers in doped Si nanowire surfaces at the nanoscale. We implement hyperspectral THz nano-imaging by combining scattering-type scanning near-field optical microscopy (s-SNOM) with THz time-domain spectroscopy (TDS). Combination of nanoscale spectroscopy and Drude model allows for measuring—noninvasively and without the need for Ohmic contacts—the local mobile carrier concentration of the differently doped semiconductor areas. "