Coulomb blockade in a nanoscale phosphorus-in-silicon island

TL;DR

This paper investigates Coulomb blockade phenomena in a nanoscale phosphorus-doped silicon island, demonstrating controlled charge transport and discussing prospects for quantum state manipulation in quantum computing applications.

Contribution

It presents a silicon single electron transistor with a phosphorus-doped island, showing Coulomb blockade effects and controllable charging energy, advancing nanoscale quantum device research.

Findings

Coulomb blockade observed with constant oscillation period

Charging energy varies with surface gate voltage

Potential for manipulating discrete quantum states

Abstract

We study the low temperature electrical transport behaviour of a silicon single electron transistor. The island and leads are defined by patterned phosphorus doped regions achieved by ion implantation through a polymer resist mask. In the device a 50 nm diameter island, containing ~600 donors and having a metallic density of states, is separated from source and drain leads by undoped silicon tunnel barriers. The central island and tunnel barriers are covered by a surface gate in a field effect transistor geometry allowing the coupling between the leads and island to be controlled. Coulomb blockade due to charging of the doped island is measured, the oscillation period is observed to be constant while the charging energy is dependent on the surface gate voltage. We discuss the possibilities of approaching the few electron regime in these structures, with the aim of observing and manipulating discrete quantum mechanical states.