Development of the Design of Super-Multiperiod Structures Grown by Molecular-Beam Epitaxy and Emitting in the Terahertz Range

An advanced theoretical approach to study super-multiperiod superlattices: theory vs experiments

“…The geometry of these SLs was inspired by the structures proposed in Ref. [8] and underwent a few modifications for output characteristics improvement, including estimated gain [9] . When the electric field is applied to such SLs, light amplification becomes possible due to the emergence of optical intersubband transitions.…”

“…All of the mentioned methods allow to simulate SLs with a large number of periods (here, SMP SLs). However, there are few works only [8,11] that include the experimental study of such SLs combined with theoretical and numerical analysis. Some of these methods even assume that the SL under consideration is infinite [33−36, 46−52] .…”

“…The THz radiation has a variety of essential applications in medicine, astronomy, and telecommunications [6,7] , which indicates the need to produce new cutting-edge tunable THz sources operating at room temperature. Multiperiod SLs are the prime candidates for this job because they have all the components required for light amplification and their designs seems to be simpler and more reliable, than designs of quantum cascade lasers (QCLs) [8,9] . The ongoing simplification of designs of QCLs towards the SLs [10,11] confirms this conclusion.…”

Carrier density distribution in AlGaAs/GaAs superlattices with different numbers of quantum wells determined by capacitance-voltage profiling

“…It is obvious, that for both quantum cascade lasers and tunable terahertz sources based on AlGaAs/GaAs superlattices with strongly and weakly coupled quantum wells, the carrier concentration and doping level is especially important, since these parameters determine gain and population inversion [4][5][6]. It was shown theoretically that for the developed terahertz source configuration there is an optimal value of the electron concentration at which generation in the terahertz region is most effective [7]. Alongside this, the distribution of electrons over the superlattice must be homogeneous to fulfill the tunneling transparency condition.…”

“…This paper is concerned with the applicability of the C-V profiling method described above for determining the carrier distribution in AlGaAs/GaAs superlattices with a different number of periods. A design solution for the layer composition and parameters of superlattice heterostructures is based on the optimal configuration proposed for terahertz radiation sources [7]. The apparent carrier concentrations obtained by C-V profiling are proven through comparison with the true concentration profiles in these structures.…”