Influence of barrier material and structure on carrier quantum confinement in GaAsBi quantum wells (QWs) is studied comprehensively. Single- and multi-QW structures were grown using solid-state molecular beam epitaxy with conventional rectangular, step-like and parabolically graded AlGaAs barrier designs. It was discovered that room temperature photoluminescence is increased by more than 50 times in the GaAsBi QWs with parabolically graded barriers (PGBs) if compared to standard rectangular and step-like structures. The enhancement of photoluminescence was reproducible within the range of growth parameters. The carrier localization and increase of trapping efficiency in GaAsBi QWs is responsible for observed enhancement in radiative properties of PGB structures. The random potential field fluctuations for carriers were increased up to 44 meV due to the blurred well-barrier interface causing the conditions for Bi content and/or well width variations. Due to the impact of self-organizing effects on the reproducibility of optical properties, the GaAsBi QWs with AlGaAs PGBs open the window for fabrication of 1.0-1.55 μm wavelength emission lasers based on GaAsBi quantum structures.

The intelligent control of autonomous vehicles has become one of the high priority tasks in development of Cyber-Physical Systems (CPS) for Industry 4.0 and Situation Awareness (SA) applications. Moving of an Autonomous Surface Vessel (ASV) to the desired area of sea is a challenging task to achieve high level of autonomy under adverse conditions. Paper focuses on the development of methodology of model-based modeling and simulation of cyber-physical nonlinear system of ASV in Simulink/MATLAB software environment. The comparison between predictive neural control and basic tracking feedback control has been presented for two maneuvers: the turn at different angles and the circular motion at final destination. Simulation results confirm the necessity and superiority of neural controller approach.

The axial C4D (Capacitively Coupled Contactless Conductivity Detection) measurement electronics for capillary electrophoresis is considered and a new improved C5D compensated detection concept is proposed and tested. Using the idle compensation channel with inversed signal and immediate analogue summation of the active and idle channel currents yields effective suppression of the influence of the parasitic stray capacitance. Preliminary experiments have confirmed at least three-fold improvements of measurement resolution. Realisation of electronics allows flexible tuning of frequency from 0.2 MHz to 2 MHz. The relatively high voltage supply of 15 V for the AC measurement units together with 24-bit accurate analogue-to-digital converter yields additional improvement for the sensitivity.DOI: http://dx.doi.org/10.5755/j01.eie.22.3.15311

Recently published experimental results for 4H–SiC diodes up to 700 °C are used to deduce the hole lifetime temperature-dependence in n-base for high temperature range. The reverse recovery measurements are interpreted by the nonisothermal drift-diffusion simulator DYNAMIT. The uncertainties from lifetimes unknown behavior in emitter layers and consequences from possible nonuniform lifetime distribution in n-base are analyzed. Results show that up to temperature 400 °C nearly quadratic dependence of lifetime versus temperature τ ~ T 2 holds. At higher temperatures lifetime growth is accelerated approximately to quartic dependence τ ~ T 4.