Thin Film Deposition

Our group is developing novel synthesis routes for thin films on planar and three dimensional substrate architectures using combinatorial approaches based on state of the art deposition techniques and their combinations such as atomic layer deposition combined with physical vapour deposition.

Atomic Layer Deposition

Examples of conformal ZnO/Al2O3 ALD films on 3D substrate architectures: pol-ystyrene spheres, Si NWs, porous polycarbonate mem-branes.
Atomic layer deposition (ALD) is an essential tool for nanoengineering. ALD relies on self-limiting surface reactions between the alternating gas precursors with a solid surface to deposit uniform ultrathin films with a subnanometer precision on geometrically complex nanostructures. We investigate ALD to develop:
  • Novel concepts for conformal coatings of high-surface and heat sensitive materials.
  • Nanolaminates for tuning materials properties.
  • Fundamental aspects of ALD precursor chemisorption and bonding on surface sites which will determine interfacial electrical and mechanical properties.
Conformal ALD TiO2 films on carbon nanotubes as a sup-port for nanostructured solar cells.
Constituent materials involve ZnO, TiO2, SiO2, MnO, and Al2O3 which serve as transparent semiconductive oxide films for solar cells, as insulating and adhesive bond material, and as nanolaminates for plasmonic applications.

Regenerated cellulose mem-brane coated with ZnO

ALD on nanostructured supports

We are developing ALD techniques to tailor the surfaces and interfaces with metal oxides on different nanostructured supports for their application in nanostructured photovoltaic devices. The nanomaterials used in these supports include carbon nanotubes, graphene, nanowires and quantum dots.

Stationary ALD

Home-built ALD reactors

We have four state of the art home-made ALD reactors, with the possibility to be modified further for any application:
  • A stationary ALD reactor with 3 inlets for the deposition of metal oxides. This ALD can be modified to use plasma and/or ozone.
  • A mobile-ALD reactor to connect to any characterization equipment for in-situ studies.
  • A dedicated ALD reactor to coat efficiently mesoporous materials with high specific surface area like aerogel or zeolite.
  • An automated ALD-PVD system to deposit nanolaminates of metals and metal oxides without breaking vacuum.

Mobile ALD
Guerra-Nunez, C.; Zhang, Y.; Li, M.; Chawla, V.; Erni, R.; Michler, J.; Park, H. G.; Utke, I., Morphology and crystallinity control of ultrathin TiO layers deposited on carbon nanotubes by temperature-step atomic layer deposition. Nanoscale 2015. DOI:10.1039/c5nr02106e
Zhang, Y.; Guerra-Nuñez, C.; Utke, I.;Michler, J.; Rossell, M. D.; Erni, R., Understanding and Controlling Nucleation and Growth of TiO2Deposited on Multiwalled Carbon Nanotubes by Atomic Layer Deposition. J. Phys. Chem. C 2015, 150203103227001.DOI:10.1021/jp511004h
Yazdani, N.; Bozyigit, D.; Utke, I.; Buchheim, J.; Youn, S. K.; Patscheider, J.; Wood, V.; Park, H. G., Enhanced charge transport kinetics in anisotropic, stratified photoanodes. ACS Appl. Mater. Interfaces 2014, 6 (3), 1389-93. DOI:10.1021/am405987t
Yazdani, N.; Chawla, V.; Edwards, E.; Wood, V.; Park, H. G.; Utke, I., Modeling and optimization of atomic layer deposition processes on vertically aligned carbon nanotubes. Beilstein J. Nanotechnol. 2014, 5, 234-244. DOI:10.3762/bjnano.5.25
Zhang, Y.; Utke, I.; Michler, J.; Ilari, G.; Rossell, M. D.; Erni, R., Growth and characterization of CNT–TiO2heterostructures. Beilstein J. Nanotechnol. 2014, 5, 946-955. DOI:10.3762/bjnano.5.108
J.A. Whitby et al. High Spatial Resolution Time-of-Flight Secondary Ion Mass Spectrometry for the Masses: A Novel Orthogonal ToF FIB-SIMS Instrument with In Situ AFM Adv. Mat. Sci. Engin. 2012 (1012) 180437, DOI: 10.1155/2012/180437.
J. Elias et al. Urchin-inspired zinc oxide as building blocks for nanostructured solar cells, Nano Energy 1(5) (2012) 696-705, DOI:10.1016/j.nanoen.2012.07.002.
R. Raghavan et al., Nanocrystalline-to-amorphous transition in nanolaminates grown by low temperature atomic layer deposition and related mechanical properties, Appl. Phys. Lett. 100, 191912 (2012); DOI: 10.1063/1.4711767.

Physical Vapour Deposition

Examples of PVD

We develop physical vapour deposition for multilayer thin films with enhanced mechanical properties. Adapting the multilayer film thicknesses to characteristic dimensions as-sociated to dislocation generation and cracking the materi-als properties can be tuned beyond the constituent materi-als. We also use resist based e-beam and UV lithography together with the in-built mini electron beam evaporator for conventional lift-off processing to prepare electrical contact pads for electronic nanodevices and solar cells.