In this work, samples of field-effect transistors were fabricated based on solid solutions of transition metal dichalcogenides and their spectral characteristics were studied using photocurrent spectroscopy. The results of a theoretical estimate of the total optical absorption of two-dimensional semiconductors at different thicknesses of the sample and for different wavelengths of optical radiation with allowance for multibeam interference are presented. It is shown that interference effects make a significant contribution to the change in the shape of the spectral characteristics of optical sensors with a change in the thickness of the photosensitive layer of transition metal dichalcogenides.

Two-dimensional molybdenum disulfide crystallites grown by mechanical exfoliation and chemical vapor deposition have been studied. It is shown that both methods can be used to obtain individual crystallites with a monoatomic thickness and similar optical properties. It is found that crystallites grown by chemical vapor deposition have a higher defect concentration than those grown by mechanical exfoliation.