Determination of free charge carrier concentration in arrays of boron doped silicon nanowires using attenuated total reflection infrared spectroscopy

Attenuated total reflection infrared spectroscopy was used to determine the free charge carrier concentration in the arrays of silicon nanowires of characteristic transverse dimension of 50–100 nm and the length of the order of 10 $\mu$m which were formed on low-doped crystalline $p$-type silicon via metal-stimulated chemical etching and subjected to additional thermodiffusion boron doping at the temperatures 850–1000$^\circ$С. It was found out that the free hole concentration varies from 5 $\times$ 10$^{18}$ to 3 $\times$ 10$^{19}$ cm$^{-3}$ depending on the annealing temperature and reaches it's maximum at 900–950$^\circ$С. The results can be used to expand the scope of silicon nanowires application in photonics, sensorics and thermoelectric power converters.