Semiconductor nanocrystal electronic structure

This first example of the utility of quadrupolar nuclei as sources of information about nano-semiconductors showed that MAS-NMR could identify a poly type that is unstable in the bulk. A second example will show that information about changes in the electronic structure of nanocrystals as a function of synthesis and treatment conditions, as well as information about different polytypes, can be obtained via measurement of Knight shifts and chemical shifts. In this extensive study 69Ga... 

Charge transport through an array of semiconductor nanocrystals is strongly affected by the electronic structure of nanocrystal surfaces. It is possible to control the type of conductivity and doping level of quantum dot crystals by adsorbing/desorbing molecular species at the nanocrystal surface. As an... 

Colloidal CdS particles 2-7 nm in diameter exhibit a blue shift in their absorption and luminescence characteristics due to quantum confinement effects [45,46]. It is known that particle size has a pronounced effect on semiconductor spectral properties when their size becomes comparable with that of an exciton. This so called quantum size effect occurs when R < as (R = particle radius, ub = Bohr radius see Chapter 4, coinciding with a gradual change in the energy bands of a semiconductor into a set of discrete electronic levels. The observation of a discrete excitonic transition in the absorption and luminescence spectra of such particles, so called Q-particles, requires samples of very narrow size distribution and well-defined crystal structure [47,48]. Semiconductor nanocrystals, or... 

Quantum size effects in semiconductor nanocrystals became an important field of research in the 1980s, when a number of groups, notably those of Brus at Bell Labs and Henglein at the Hahn Meitner Institute, published seminal papers on the effects of the size of semiconductor colloids on their optical properties and correlated crystal size with changes in electronic band structure. 

Electronic absorption spectroscopy has played a pivotal role in the development of methods for synthesizing pure semiconductor nanocrystals. Nanocrystal sizes, size distributions, growth kinetics, growth mechanisms, and electronic structures have all been studied in detail using electronic absorption spectroscopy. 

Theoretical calculations of the electronic structure of metal and semiconductor nanocrystals throw light on the size-... 

Efros AL, Rosen M (2000) The electronic structure of semiconductor nanocrystals. Annual Rev. Mater. 

I 7 7 Electronic Structure and Spectroscopy of Semiconductor Nanocrystals energy term Vp(r) in the Hamiltonian... 

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