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Atomic layer deposition of amorphous tin-gallium oxide films
- Publication Year :
- 2019
- Publisher :
- Uppsala universitet, Fasta tillståndets elektronik, 2019.
-
Abstract
- A wide range of applications benefit from transparent semiconducting oxides with tunable electronic properties, for example, electron transport layers in solar cell devices, where the electron affinity is a key parameter. Presently, a few different ternary oxides are used for this purpose, but the attainable electron affinity range is typically limited. In this study, the authors develop a low-temperature atomic layer deposition (ALD) process to grow amorphous Sn1-xGaxOy thin films from dimethylamino-metal complexes and water. This oxide is predicted to provide a wide selection of possible electron affinity values, from around 3 eV for pure Ga2O3 to 4.5 eV for pure SnO2. The ALD process is evaluated for deposition temperatures in the range of 105-195 degrees C by in situ quartz crystal microbalance and with ex situ film characterization. The growth exhibits an ideal-like behavior at 175 degrees C, where the film composition can be predicted by a simple rule of mixture. Depending on film composition, the growth per cycle varies in the range of 0.6-0.8 angstrom at this temperature. Furthermore, the film composition for a given process appears insensitive to the deposition temperature. From material characterization, it is shown that the deposited films are highly resistive, fully amorphous, and homogeneous, with moderate levels of impurities (carbon, nitrogen, and hydrogen). By tailoring the metal cation ratio in films grown at 175 degrees C, the optical bandgap can be varied in the range from 2.7 eV for SnO2 to above 4.2 eV for Ga2O3. The bandgap also varies significantly as a function of deposition temperature. This control of properties indicates that Sn1-xGaxOy is a promising candidate for an electron transport layer material in a wide electron affinity range. Published by the AVS.
- Subjects :
- Solid-state chemistry
Materials science
chemistry.chemical_element
Materialkemi
02 engineering and technology
Electron
01 natural sciences
law.invention
Condensed Matter::Materials Science
Atomic layer deposition
law
Electron affinity
Teknik och teknologier
0103 physical sciences
Solar cell
Materials Chemistry
010302 applied physics
business.industry
Surfaces and Interfaces
021001 nanoscience & nanotechnology
Condensed Matter Physics
Electron transport chain
Surfaces, Coatings and Films
Amorphous solid
chemistry
Optoelectronics
Engineering and Technology
0210 nano-technology
business
Tin
Den kondenserade materiens fysik
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....ae1e31f2e56cd7e3130445b7eb75f4da