Nanoscale physics
Quantum theory of energetic parameters in two-well nanostructure, being a main operating element of broadband photodetector functioning in far IR range
Tkach M.V., Hutiv V.V., Seti Ju.O., Voitsekhivska O.M.
Department of Theoretical Physics and Computer Simulation, Yuriy Fedkovych Chernivtsi National University,2, Kotsyubinsky Str., Chernivtsi-58012, Ukraine,
E-mail: hutiv. vasyl@chnu. edu. ua.

For the stable operation of quantum nanostructures, being the main elements of broadband photodetectors functioning in a very far infrared range, they should demonstrate peculiar characteristics: provide high detective properties over the whole width of the absorption band in the desired range of electromagnetic field energies at minimum dark current. Due to the significant mismatch in the size of the unit cells of anisotropic materials of quantum wells and barriers, it is difficult to produce stable high-quality photodetectors. Therefore, intensive research is underway into such isotropic materials, whose quantum wells and barriers have well-matched unit cell sizes and, with the optimal geometric design, can meet these requirements for the successful operation of QWIPs.
In the proposed paper, a quantum mechanical calculation of the electron spectrum, wave functions and oscillator forces of quantum transitions under the action of an absorbed electromagnetic field in a nano heterostructure consisting of two wide quantum wells, but with an inverted internal structure of potential profile is performed. The results of numeric calculation show that by choosing the geometric parameters of the inner profile (widths and heights of the inner quantum wells and barriers) of the main element of photodetector, it is possible to ensure such ratio between the width and the maximum of absorption band range, which optimizes the operation of broadband detector in the demanded far IR range, as the "window" of atmospheric transparency.

1.	Tkach M.V., Seti Ju.O., Voitsekhivska O.M Diagram technique in the method of Green’s functions for the quasiparticles interacting with phonons. Chernivtsi: Chernivtsi National University. – 2019. – 164 p.