Low-frequency electronic noise in superlattice and random-packed thin films of colloidal quantum dots

Adane Geremew; Caroline Qian; Alex Abelson; Sergey Rumyantsev; Fariborz Kargar; Matt Law; Alexander A Balandin

doi:10.1039/c9nr06899f

Low-frequency electronic noise in superlattice and random-packed thin films of colloidal quantum dots

Nanoscale. 2019 Nov 14;11(42):20171-20178. doi: 10.1039/c9nr06899f. Epub 2019 Oct 16.

Authors

Adane Geremew¹, Caroline Qian², Alex Abelson³, Sergey Rumyantsev⁴, Fariborz Kargar¹, Matt Law⁵, Alexander A Balandin⁶

Affiliations

¹ Nano-Device Laboratory (NDL), Department of Electrical and Computer Engineering, University of California, Riverside, California 92521, USA. balandin@ece.ucr.edu.
² Department of Chemical and Biomolecular Engineering, University of California, Irvine, California 92697, USA.
³ Department of Materials Science and Engineering, University of California, Irvine, California 92697, USA.
⁴ Nano-Device Laboratory (NDL), Department of Electrical and Computer Engineering, University of California, Riverside, California 92521, USA. balandin@ece.ucr.edu and CENTERA Laboratories, Institute of High-Pressure Physics, Polish Academy of Sciences, Warsaw 01-142, Poland.
⁵ Department of Chemical and Biomolecular Engineering, University of California, Irvine, California 92697, USA and Department of Materials Science and Engineering, University of California, Irvine, California 92697, USA and Department of Chemistry, University of California, Irvine, California 92697, USA.
⁶ Nano-Device Laboratory (NDL), Department of Electrical and Computer Engineering, University of California, Riverside, California 92521, USA. balandin@ece.ucr.edu and Phonon Optimized Engineered Materials (POEM) Center, Materials Science and Engineering Program, University of California, Riverside, California 92521, USA.

PMID: 31616880
DOI: 10.1039/c9nr06899f

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 in the ordered and random quantum dot films. 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.