We describe a mechanism that links the long-range potential fluctuations induced by charged defects to the low-frequency resistance noise widely known as l/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 have 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.
- Amorphous silicon
- l/f noise
- Long-range potential fluctuations