Shot Noise in Negative-Differential-Conductance Devices

TL;DR

This study compares shot-noise behavior in two NDC devices at 4.2 K, revealing that charge accumulation causes noise enhancement rather than system instability.

Contribution

It demonstrates that shot-noise enhancement in NDC devices is due to charge accumulation, contrasting with previous assumptions linking it to system instability.

Findings

Resonant-tunneling diode shows increased noise in NDC region.

Superlattice tunnel diode maintains Poissonian noise in NDC region.

Charge accumulation, not instability, causes shot-noise enhancement.

Abstract

We have compared the shot-noise properties at T = 4.2 K of a double-barrier resonant-tunneling diode and a superlattice tunnel diode, both of which exhibit negative differential-conductance (NDC) in their current-voltage characteristics. While the noise spectral density of the former device was greatly enhanced over the Poissonian value of 2eI in the NDC region, that of the latter device remained 2eI. This result implies that charge accumulation, not system instability, is responsible for shot-noise enhancement in NDC devices.