Aluminium arsenide-based single-electron transistor characteristics and its potential for charge detection

A single electron transistor (SET) based on an aluminium arsenide (AlAs) monolayer quantum dot (QD) is computationally studied for charge sensing applications. Electronic transport properties are calculated using the density functional theory (DFT) framework. A noticeable reduction in ionisation energy and electron affinity is observed in the SET environment compared to the isolated state. The variation of total energy with gate voltage ( V G ) is evaluated for various charge states, which shows nearly a linear dependence. The positively charged states stabilise under negative gate bias and vice versa. The charge stability diagrams (CSD), along with their line scans and normalised differential conductivity plots, are analysed to capture single-electron transport features. The results capture the boundaries of Coulomb-blocked regions and the corresponding charge transition lines. The distinct peaks at the degeneracy points in the horizontal scan and step-like structures in the vertical scan confirm quantised charge transport behaviour through the QD. The nearest degeneracy point under positive gate bias occurs at V G ≈ 0 . 33 V, while under negative biasing, it appears at approximately − 1 . 6 V. Thus, operation under positive gate potential is energetically more favourable. The effect of electrode work function on CSD and the total energy is further examined. The degeneracy points shift systematically towards positive V G values as the work function increases. The total energy surface profile shows strong dependence on charge and work function. Thus, AlAs-based SET may serve as a reliable platform for precise charge detection and also highlights the potential of two-dimensional group III-V semiconductors for future quantum devices. • Aluminium arsenide based single electron transistor analysed for charge sensing. • Energy contours vary with gate bias and work function, showing strong tunability. • CSD analysis identifies clear Coulomb blockade and charge transitions. • First degeneracy at V G ≈ 0 . 33 V shows positive gate bias is energetically favoured. • Degeneracy points shift with electrode work function towards positive gate voltage.