Single-electron transport through stabilised silicon nanocrystals

Abstract

We have fabricated organically capped stable luminescent silicon nanocrystals with narrow size distribution by a novel, high yield and easy to implement technique. We demonstrate transport measurements of individual silicon nanocrystals by scanning tunnelling microscopy at a low temperature in a double-barrier tunnel junction arrangement in which we observed pronounced single electron tunnelling effects. The tunnelling spectroscopy of these nanocrystals with different diameters reveals quantum confinement induced bandgap modifications. Furthermore, from the features in the tunnelling spectra, we differentiate several energy contributions arising from electronic interactions inside the nanocrystal. By applying a magnetic field, we have detected a variation in the differential conductance profile that we attribute to arising from higher order tunnelling processes. We have also systematically simulated our experimental data with the Orthodox theory, and the results show good agreement with the experiment. The study establishes a correlation between the nanocrystal size and quantum confinement induced band-structure modifications which will pave the way to devise tailored nanocrystals.

Unraveling the Relevance of Electron and Hole Transfer in Lead Halide Perovskite Nanocrystals on Current Conduction

“…However, an in-depth investigation at the single PNC level is still lacking. Though the local conductance in a single molecular setup has been addressed for other semiconducting nanostructures of silicon, PbS, and ZnS, − a proper assessment of the conductance for PNC is unclear to date. Herein, with a series of spectroscopic and current-sensing atomic force microscopic techniques (CS-AFM), we explore the criticality of band-energy alignment for CT and its impact on the current ( I )–voltage ( V ) characteristics and conductance with redox-active quinones (QNs), menadione (MD), and anthraquinone (AQ) across a single electrode–PNC–electrode junction.…”

Remarkable Noise Reduction in High-Stability Self-Powered Doped Graphene/Si-Quantum Dot Broadband Photodetectors by Using Graphene Quantum Dots as an Interlayer

“…Here, the work function of the TFSA-GR is by our measurements, but the rest of the band parameters are by others, as published in literature. ,− The p-SiQDs:SiO 2 film is composed of alternating layers of p-SiQDs and SiO 2 , through which the carrier transport is governed by tunneling. , In our previous report, negative differential resistance under illumination, typical of the tunneling behavior, was observed for similar SiQD materials and their physical mechanism was discussed in detail. Based on this and other reports, , the tunneling mechanism is widely accepted for explaining the current flow within SiQDs:SiO 2 . The p-doping of the SiQDs with B was also analyzed in our previous work .…”

Application of Scanning Tunneling Microscopy and Spectroscopy in the Studies of Colloidal Quantum Qots

“…With high spatial and energy resolution, STM can not only be used to characterize the surface structure, but also accurately measure the local electrical properties of the sample through STS. This provides a powerful way to study the electrical properties of semiconductor nanocrystals, [25,132,133] which plays an important role in the study of the electrical properties of colloidal QDs.…”