International Journal on Technical and Physical Problems of Engineering, cilt.14, sa.3, ss.155-160, 2022 (Scopus)
In recent years, both physical-chemical and electrical properties of nanotubes based on carbon nanomaterials have been actively studied. At the same time, the photoelectric properties of carbon nanotubes are of undoubted interest. A study was made of the photosensitivity spectrum of a nanotubes based on pure carbon (CNTs) in the wavelength range λ=400-900 nm at five values of the bias voltage U applied to the sample: U=1 V, 3 V, 5 V, 7 V and 9V. The analysis shows that that an increase in the bias voltage applied to the sample of the CNTs under study leads to an expansion of the range of zero or weak photosensitivity and to a decrease in the magnitude of the photosensitivity peaks. In particular, at U=9 V, the sample loses photosensitivity in almost the entire studied wavelength range λ=400-900 nm, and therefore it is not effective to use it as a detection detector at such a voltage value. The widest photosensitivity range and the highest sensitivity value are observed at a voltage of U=1 V. At the same time, at a wavelength of λ~715 nm, the most significant photocurrent peak is reached, equal to Ip~0.2 μA. This means that CNTs at voltage U=1 V can be effectively used as radiation detectors in several radiation ranges. Experimental points and curves approximating them for I-V characteristics of the studied nanotube samples are presented at six wavelengths: λ~640 nm, λ~720 nm, λ~740 nm, λ~760 nm, λ~780 nm, and λ~880 nm. It is shown that the approximating curves are well described by polynomials of the fourth degree. It has been determined that at λ~720 nm the I-V characteristic exhibits a very weak photosensitivity in almost the entire voltage range of 1-9 V. As the wavelength increases, there is a tendency for the photosensitivity peak to shift to the left towards lower voltage values, while the photocurrent peak decreases with each shift.