Localization effects in the tunnel barriers of phosphorus-doped silicon quantum dots

TL;DR

This paper investigates the origin of negative differential conductance in phosphorus-doped silicon quantum dots, attributing it to weak localization effects and shallow energy defects, with experimental and simulation analyses across various conditions.

Contribution

It provides a novel explanation linking localization effects and shallow defects to tunneling behavior in silicon quantum dots, supported by experimental data and simulations.

Findings

Negative differential conductance observed and analyzed.

Localization effects and shallow defects explain tunneling behavior.

Magnetic field effects discussed in context of localization.

Abstract

We have observed a negative differential conductance with singular gate and source-drain bias dependences in a phosphorus-doped silicon quantum dot. Its origin is discussed within the framework of weak localization. By measuring the current-voltage characteristics at different temperatures as well as simulating the tunneling rates dependences on energy, we demonstrate that the presence of shallow energy defects together with an enhancement of localization satisfactory explain our observations. Effects observed in magnetic fields are also discussed.