The effect of ZnO surface conditions on the electronic structure of the ZnO/CuPc interface

Journal Article · Mon Feb 21 00:00:00 EST 2011 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.3555440· OSTI ID:21518292

Park, Sang Han; Kim, Hyo Jin; Cho, Mann-Ho ^[1]; Yi, Yeonjin ^[2]; Cho, Sang Wan ^[3]; Yang, Jaehyun; Kim, Hyoungsub ^[4]

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1. Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of)
2. Division of Industrial Metrology, KRISS, Daejeon 305-340 (Korea, Republic of)
3. Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215 (United States)
4. School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

The interfacial electronic structures of zinc oxide (ZnO)/copper-phthalocyanine (CuPc) were investigated by in situ x-ray and ultraviolet photoelectron spectroscopy (UPS) to determine the effects of air contamination on the ZnO substrate. UPS spectra showed that the 0.2 eV of the interface dipole is generated at the interface of the air exposed ZnO/CuPc while the interface of the annealed ZnO/CuPc generated -0.2 eV. In both cases, no band bending was observed. On the other hand, band bending at 0.3 eV and an interface dipole of 0.2 eV were observed at the interface of the sputter cleaned ZnO/CuPc. The energy offset between the conduction band maximum of ZnO and the highest occupied molecular orbital of CuPc was determined to be 0.6-0.7 eV for the contaminated ZnO interface while the offset was 1.0 eV for the cleaned ZnO interface. Contaminating moisture has little effect on the offset while the charge transfer was blocked and the offset was decreased in the presence of hydrocarbons.

• OSTI ID: 21518292
• Journal Information: Applied Physics Letters, Vol. 98, Issue 8; Other Information: DOI: 10.1063/1.3555440; (c) 2011 American Institute of Physics; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
CONTAMINATION
COPPER COMPOUNDS
DECONTAMINATION
DEPOSITION
ELECTRONIC STRUCTURE
HYDROCARBONS
INTERFACES
LAYERS
MOLECULAR ORBITAL METHOD
PHOTOELECTRON SPECTROSCOPY
PHTHALOCYANINES
SEMICONDUCTOR MATERIALS
SPECTRA
SPUTTERING
SUBSTRATES
SURFACES
ULTRAVIOLET RADIATION
X RADIATION
ZINC OXIDES
CALCULATION METHODS
CHALCOGENIDES
CLEANING
DYES
ELECTROMAGNETIC RADIATION
ELECTRON SPECTROSCOPY
HEAT TREATMENTS
HETEROCYCLIC COMPOUNDS
IONIZING RADIATIONS
MATERIALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RADIATIONS
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS
ZINC COMPOUNDS