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Nearly Monodispersed Colloidal Semiconductor Nanocrystals Fabrication Through Saturated Ionic Layer Adsorption

Adhikari, Prakash
http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1466788142

Abstract Details

2016, Master of Science (MS), Bowling Green State University, Physics.
The nanostructure of semiconductor materials exhibits different properties than those of their corresponding bulk structures. It has attracted considerable interest in scientific research and technology. In spite of their potential to be the building blocks of the next generation of technology, their use in such applications is not ubiquitous. Some of the bottlenecks that hinder the use of nanocrystals are the polydispersities in shape and size, poor crystallinity, non-uniform surface passivation, less control over the nanocrystal stoichiometry, etc. In this work, we demonstrate a technique to fabricate high quality nearly monodispersed colloidal semiconductor nanocrystals, exhibiting size dispersion below 5%. The strategy of growing nearly monodispersed semiconductor nanocrystals depends on the sequential deposition of the fully saturated cationic and anionic monolayers onto small diameter nano-clusters. In each layer of deposition, a well-defined layer size is added, which ultimately increases the size of the nanocrystals but decreases the size dispersion. Each ionic monolayer is deposited on the surface of the nano-clusters (grown through the hot injection process) at room temperature via colloidal atomic layer deposition that employs a two-solvent mixture to separate the nanoparticles and precursor phases. The reaction is initiated by agitating the reaction mixture, and upon the completion of the reaction, the two phases separate from each other so that the unreacted precursors can be discarded, which ultimately nullifies any chances of secondary nucleation. Here, the experiment is carried out with emphasis on CdS semiconductor nanocrystals, and Cd2+ and S2- ions were sequentially deposited onto the starting CdS cluster “seeds”. The result exhibits a decrease in the size dispersion and gives more control over the nanocrystal surface composition. The technique offers an excellent batch-to-batch reproducibility and is amenable to other semiconductor nanocrystals. It can pave an alternative path to prevailing traditional hot injection strategies of nanoparticle growth.
Mikhail Zamkov, Dr. (Advisor)
Lewis P. Fulcher, Dr. (Committee Member)
Alexey T. Zayak, Dr. (Committee Member)
46 p.
Physics
Monodispersed; Colloidal; Nanocrystals; Fabrication;

Recommended Citations

Citations

  • Adhikari, P. (2016). Nearly Monodispersed Colloidal Semiconductor Nanocrystals Fabrication Through Saturated Ionic Layer Adsorption [Master's thesis, Bowling Green State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1466788142

    APA Style (7th edition)

  • Adhikari, Prakash. Nearly Monodispersed Colloidal Semiconductor Nanocrystals Fabrication Through Saturated Ionic Layer Adsorption . 2016. Bowling Green State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1466788142.

    MLA Style (8th edition)

  • Adhikari, Prakash. "Nearly Monodispersed Colloidal Semiconductor Nanocrystals Fabrication Through Saturated Ionic Layer Adsorption ." Master's thesis, Bowling Green State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1466788142

    Chicago Manual of Style (17th edition)

bgsu1466788142
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© 2016, all rights reserved.
This open access ETD is published by Bowling Green State University and OhioLINK.