The effect of a charge trap in the vicinity of the quantum-dot on the charge stability diagram of a single electron transistor

In this article, we explored the effect of a single charge trap on the charge stability diagram of the quantum-dot-based single-electron transistor. We investigated anomalies in the coulomb characteristic diagram, system energy, occupation probabilities, and quantum dot conductivity arising from the electrostatic interaction between the main dot and this charge trap. The anomalies were studied for various locations of the trap, mainly when the trap is located at the source or drain sides of the device. A significant enhancement in quantum dot conductivity was observed by bringing the main quantum dot closer to the source and drain with increased coupling capacitors. The trap, capacitively linked to the quantum dot, has two charge states, either empty or occupied by a single electron. Considering various quantum states, we solved the master equation using Fermi’s golden rule to obtain tunneling rates and the matrix of tunneling coefficients. Inverting the coefficient matrix allowed us to determine the probability of each quantum state. The results of this analysis have been validated by comparing simulation results with experimental data. In conclusion, our study provides a valuable tool for detecting charge presence in a trap near a quantum dot, potentially applicable for the readout of quantum gates.