Investigation of the surface chemical and electronic states of pyridine-capped CdSe nanocrystal films after plasma treatments using H{sub 2}, O{sub 2}, and Ar gases

Journal Article · Thu Jul 15 00:00:00 EDT 2010 · Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films

DOI:https://doi.org/10.1116/1.3431079· OSTI ID:22053723

Wang, Seok-Joo; Kim, Hyuncheol; Park, Hyung-Ho; Lee, Young-Su; Jeon, Hyeongtag; Chang, Ho Jung ^[1]

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1. Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

Surface chemical bonding and the electronic states of pyridine-capped CdSe nanocrystal films were evaluated using x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy before and after plasma treatments using H{sub 2}, O{sub 2}, and Ar gases from the viewpoint of studying the effects of surface capping organic molecules and surface oxidation. Surface capping organic molecules could be removed during the plasma treatment due to the chemical reactivity, ion energy transfer, and vacuum UV (VUV) of the plasma gases. With O{sub 2} plasma treatment, surface capping organic molecules were effectively removed but substantial oxidation of CdSe occurred during the plasma treatment. The valence band maximum energy (E{sub VBM}) of CdSe nanocrystal films mainly depends on the apparent size of pyridine-capped CdSe nanocrystals, which controls the interparticle distance, and also on the oxidation of CdSe nanocrystals. Cd-rich surface in O{sub 2} and H{sub 2} plasma treatments partially would compensate for the decrease in E{sub VBM}. After Ar plasma treatment, the smallest value of E{sub VBM} resulted from high VUV photon flux, short wavelength, and ion energy transfer. The surface bonding states of CdSe had a strong influence on the electronic structure with the efficient strip of capping molecules as well as different surface oxidations and surface capping molecule contents.

• OSTI ID: 22053723
• Journal Information: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Vol. 28, Issue 4; Other Information: (c) 2010 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1553-1813
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
77 NANOSCIENCE AND NANOTECHNOLOGY
BOUND STATE
CADMIUM SELENIDES
CHEMICAL BONDS
ELECTRONIC STRUCTURE
ENERGY TRANSFER
FAR ULTRAVIOLET RADIATION
HYDROGEN
IONS
NANOSTRUCTURES
OXIDATION
OXYGEN
PHOTONS
PLASMA
PYRIDINE
THIN FILMS
VALENCE
X-RAY PHOTOELECTRON SPECTROSCOPY