Long-range fluctuations of random potential landscape as a mechanism of 1/f noise in hydrogenated amorphous silicon

TL;DR

This paper proposes a microscopic mechanism linking long-range potential fluctuations caused by charged defects to 1/f noise in hydrogenated amorphous silicon, with calculations matching experimental data.

Contribution

It introduces a first-principles calculation method for noise spectrum based on defect-induced potential fluctuations, applicable to amorphous semiconductors.

Findings

Theoretical noise intensity agrees with experimental measurements.

The mechanism is general and applicable to systems with charged defects.

First-principles calculation can predict 1/f noise in amorphous materials.

Abstract

We describe a mechanism, which links the long-range potential fluctuations induced by charged defects to the low frequency resistance noise widely known as 1/f noise. This mechanism is amenable to the first principles microscopic calculation of the noise spectrum, which includes the absolute noise intensity. We have performed such a calculation for the thin films of hydrogenated amorphous silicon (a-Si:H) under the condition that current flows perpendicular to the plane of the films, and found a very good agreement between the theoretical noise intensity and the measured one. The mechanism described is quite general. It should be present in a broad class of systems containing poorly screened charged defects.