Optical Reflectivity of Spin-Coated Multilayered ZnO and Al:ZnO Thin Films

Autor: Robert McCormack, Darragh Buckley, Colm O'Dwyer, David McNulty, Peter J. Parbrook, Vitaly Z. Zubialevich
Rok vydání: 2017
Předmět:
Engineering drawing
Materials science
X ray diffraction
Band gap
Thin films
X ray photoelectron spectroscopy
Coating methods
High resolution transmission electron microscopy
Reflection
Semiconductor materials
Electrical conductance
Solution-processed
Electrical resistance and conductance
X-ray photoelectron spectroscopy
Coatings
Semiconductor devices
Zinc oxide
Semiconductor doping
Thin film
High-resolution transmission electron microscopy
Films
Flexible electronics
Optical transparency
Substrates
Dopant
business.industry
Film thickness
Thin film transistors
Wide band gap semiconductors
eye diseases
Energy gap
Flexible displays
Optical reflectivity
Electronic conductivity
Thin-film transistor
Film growth
Optoelectronics
Channel materials
sense organs
Crystalline structure
business
Transmission electron microscopy
Zdroj: ECS Meeting Abstracts. :1296-1296
ISSN: 2151-2043
DOI: 10.1149/ma2017-01/27/1296
Popis: Zinc oxide (ZnO) and its doped counterparts such as Al:ZnO are extensively investigated as indium-free alternatives for oxide electronics including solar cells, light emitting diodes and also display technologies. For the latter application, thin film transistor (TFT) devices are the building-block structures. High fidelity TFTs require conductive channel materials, with good field effect mobility for majority carriers and tunable optical transparency. Controlling growth, doping, crystallization, and thickness of thin films of these materials is required in order to improve and control physical properties, primarily electronic conductivity and optical transparency. With the advent of flexible electronics and curved TFT-based display panels, low cost, solution-processed methods are important and provide scalable coating methods on a range of substrates. This work demonstrates the changes to the morphology, crystalline structure, optical reflectivity and electrical conductance of solution-processed ZnO thin films by the inclusion of an aluminium dopant during spin-coating. The is work also determines the compositional chemical state of the Al:ZnO structures compared to ZnO using X-ray photoelectron spectroscopy in conjunction with detailed X-ray diffraction and transmission electron microscopy examination of the film morphology. We also demonstrate a method of determining the optical thickness of multilayer thin films using simple, non-destructive angle-resolved reflectance measurements. Using optical interference, the optical thickness of the multi-layered deposited ZnO and Al:ZnO can be determined and show good agreement with the thicknesses measured by transmission electron microscopy of electron transparent lamellar cross-sections. We also show the visible and near-infra red (VIS-NIR) light spectroscopy of ZnO and Al:ZnO multi-layered thin film structures grown on oxidized silicon substrates also define the growth conditions and processing to provide tunable antireflection coatings of ZnO and AZO.
Databáze: OpenAIRE