Nanoscience and Nanotechnology letters,Vol.4,(2012),Nanoscience and Nanotechnology Letters, Vol.2, (2010),American Institute of Physics Conference Proceedings ,Vol.1276 (2010) (original) (raw)

Low-Temperature Annealing for Highly Conductive Lead Chalcogenide Quantum Dot Solids

The Journal of Physical Chemistry C, 2011

Electrical conductivity in quantum dot solids is crucial for application in devices. In addition to the wellknown ligand exchange strategies for enhanced conductivity, the current study examined the optical, structural, and electrical properties of ethanedithiol-treated layer-by-layer (LbL) assembled quantum dot solid (QDS) films following low-temperature annealing (room temperature to 170°C). As the annealing temperature increased, it was induced that the average separation between nanocrystal quantum dots is decreased, and accordingly, the overall conductivity of the QDS increased exponentially. From a simplified percolation model, the activation energy of temperature-dependent quantum dot attachment was estimated to be around 0.26-0.27 eV both for PbS and PbSe quantum dot solids. Furthermore, the results of this study indicated that device applications requiring higher conductivity, attainable through high-temperature annealing, may also require repassivation after annealing.

Strong Quantum Confined Lead Sulphide Quantum Dots using Ionic Reaction and Their properties

ES Materials & Manufacturing

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Quantum dots for memory applications

physica status solidi (a), 2013

In this paper, we review the fabrication and the electrical characteristics of metal-insulator-semiconductor (MIS) devices with semiconductor quantum dots (QD) embedded into the gate dielectric. Our results originate from experiments performed the last decade and cover Si QDs realized by low-energy ion-beam synthesis (IBS) as well as GaN QDs formed by molecular beam deposition (MBD). Besides the basic capacitance-to-voltage (C-V) and current-to-voltage (I-V) characterization, the memory properties of the fabricated MIS devices were investigated in terms of memory window under pulse operation and charge retention. The optimization of Si-QD memory cells is reviewed and a methodology for both the extraction of various device parameters and the identification of mechanisms governing the charge loss process are presented. GaN QDs, which exhibit negative conduction band-offset with respect to the Si conduction band, offer an interesting alternative to Si QDs as discussed herein based on our investigations of GaN-QD capacitors fabricated by a complementary-metal-oxide-semiconductor (CMOS) compatible process.

Nonvolatile Resistive Switching Memory Device Employing CdSe/CdS Core/Shell Quantum Dots as an Electrode Modification Layer

ACS Applied Electronic Materials, 2020

Accompanied with great advantages in various fields of performance, memristors show huge potential in the next generation of mainstream storage devices. However, their random distribution of resistance switching voltage has always been one of the problems in applications. In this present work, a nonvolatile resistive switching memory device was proposed, which employed CdSe/CdS core/shell quantum dots (QDs) assembled as an electrode modification layer with the device configuration of Pt/CdSe-CdS QDs/TaO x /Ta. The device possesses multiple excellent resistance switching characteristics such as lower and more consistent set/reset threshold voltage and better endurance performance, which is considered as the effect of the electrode modification layer based CdSe/CdS core/shell QDs. A model with uneven QDs/Pt electrode interface was put forward to explain the different resistance switching behaviors, which may be beneficial to the development of existing research about memristors based on metal oxides and quantum dots.

Strong Quantum Confined Lead Sulphide Quantum Dots using Ionic Reaction and Their Properties ES Materials & Manufacturing

ES Materials & Manufacturing, 2019

View Article Online Lead sulfide quantum dots have been synthesized from a cost-effective and facile chemical method namely ionic reaction using lead nitrate and sodium sulphide as precursors in aqueous solutions. The as prepared nanocrystals are characterized for their optical, structural and electrochemical properties using optical absorption spectroscopy, transmission electron microscopy and cyclic voltammetry respectively. The PbS quantum dots have an average size of 6 nm. The strong size quantization is observed from cyclic voltammetry and absorption spectroscopy.

Materials for Future Quantum Dot-Based Memories

Journal of Nanomaterials, 2013

The present paper investigates the current status of the storage times in self-organized QDs, surveying a variety of heterostructures advantageous for strong electron and/or hole confinement. Experimental data for the electronic properties, such as localization energies and capture cross-sections, are listed. Based on the theory of thermal emission of carriers from QDs, we extrapolate the values for materials that would increase the storage time at room temperature to more than millions of years. For electron storage, GaSb/AlSb, GaN/AlN, and InAs/AlSb are proposed. For hole storage, GaSb/Al 0.9 Ga 0.1 As, GaSb/GaP, and GaSb/AlP are promising candidates.

Lead chalcogenide quantum dots for photoelectric devices

Russian Chemical Reviews, 2020

The review concerns the state of the art in methods of synthesis of colloidal lead chalcogenide quantum dots (QDs). The most recent data on the mechanisms of chemical transformations involving various precursors are discussed. Particular attention is paid to the influence of (i) trace impurities in the reactants used and (ii) post-synthesis treatment on the physicochemical properties of QDs used in photoelectric devices.The bibliography includes 129 references.