Electrospray organometallic chemical vapor deposition—A novel technique for preparation of II–VI quantum dot composites

A novel technique combining electrospray and organometallic chemical vapor deposition (OMCVD) has been developed for the synthesis of new II–VI quantum dot composites. CdSe nanocrystals (quantum dots) of selected size are dispersed in a pyridine/acetonitrile mixture. The nanocrystals are transferred by electrospray into the growth zone of an OMCVD reactor and codeposited on a ZnSe matrix grown from hydrogen selenide and diethyl zinc. Composites consisting of CdSe nanocrystals and an amorphous or polycrystalline ZnSe matrix have been deposited on glass substrates at temperatures of 150–250 °C. Room‐temperature absorption and photoluminescence spectra show optical transitions characteristic of the initial nanocrystal dispersions. The emission wavelength may be tuned in a broad spectral region by incorporating nanocrystals of varying sizes. The composites have been characterized by Auger electron spectroscopy, high resolution transmission electron microscopy, and scanning transmission electron microscopy.

[1]  M. Mann,et al.  Electrospray ionization for mass spectrometry of large biomolecules. , 1989, Science.

[2]  A. Gomez,et al.  Charge and fission of droplets in electrostatic sprays , 1994 .

[3]  T. Koyama,et al.  Fabrication of microcrystallites of II–IV compound semiconductors by laser ablation method , 1992 .

[4]  K. Vahala,et al.  Nanometer-scale GaAs clusters from organometallic precursors , 1992 .

[5]  Louis E. Brus,et al.  Nucleation and Growth of CdSe on ZnS Quantum Crystallite Seeds and Vice Versa, in Inverse Micelle Media , 1990 .

[6]  P. J. Parbrook,et al.  CONTROL OF PREREACTION IN THE METALORGANIC CHEMICAL VAPOUR DEPOSITION OF ZINC- AND CADMIUM-BASED CHALCOGENIDES , 1991 .

[7]  J. Fenn,et al.  Ion formation from charged droplets: Roles of geometry, energy, and time , 1993, Journal of the American Society for Mass Spectrometry.

[8]  T. Mallouk,et al.  Demonstration of a shell-core structure in layered cadmium selenide-zinc selenide small particles by x-ray photoelectron and Auger spectroscopies , 1992 .

[9]  Photoluminescence from nanocrystallites embedded in hydrogenated amorphous silicon films prepared by plasma enhanced chemical vapor deposition , 1994 .

[10]  K. Vahala,et al.  Fabrication of semiconductor quantum dots , 1991 .

[11]  H. Weller.  Colloidal Semiconductor Q‐Particles: Chemistry in the Transition Region Between Solid State and Molecules , 1993 .

[12]  Norman Herron,et al.  Nanometer-sized semiconductor clusters: materials synthesis, quantum size effects, and photophysical properties , 1991 .

[13]  L. Brus,et al.  Quantum crystallites and nonlinear optics , 1991 .

[14]  M. Bawendi,et al.  Synthesis and characterization of nearly monodisperse CdE (E = sulfur, selenium, tellurium) semiconductor nanocrystallites , 1993 .

[15]  K. Vahala,et al.  Vapor phase synthesis of crystalline nanometer‐scale GaAs clusters , 1992 .