Low-Frequency Electronic Noise in Superlattice and Random-Packed Thin Films of Colloidal Quantum Dots

TL;DR

This study investigates low-frequency electronic noise in colloidal quantum dot films with different structural orderings and ligand chemistries, revealing insights into noise characteristics relevant for photodetector applications.

Contribution

It provides a comparative analysis of noise in ordered, weakly-ordered, and random-packed PbSe quantum dot films, highlighting the influence of film structure and ligand chemistry on noise behavior.

Findings

Ordered films exhibit lower noise levels than disordered ones.

Noise spectra include a Lorentzian component indicating generation-recombination processes.

Ligand chemistry significantly affects the magnitude of electronic noise.

Abstract

We report measurements of low-frequency electronic noise in ordered superlattice, weakly-ordered and random-packed thin films of 6.5 nm PbSe quantum dots prepared using several different ligand chemistries. For all samples, the normalized noise spectral density of the dark current revealed a Lorentzian component, reminiscent of the generation-recombination noise, superimposed on the 1/f background (f is the frequency). An activation energy of 0.3 eV was extracted from the temperature dependence of the noise spectra. The noise level in the ordered films was lower than that in the weakly-ordered and random-packed films. A large variation in the magnitude of the noise spectral density was also observed in samples with different ligand treatments. The obtained results are important for application of colloidal quantum dot films in photodetectors.