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Research_

Applied and plasma physics

New physics applications in industry, medicine and the environment
We explore new areas of physics with applications spanning novel plasma sources, thin film materials, surface modifications and devices for medicine, manufacturing, microelectronics, renewable energy and sustainability.

Our research

The Applied and Plasma Physics research group explores exciting new areas of physics with 'real world' applications in industry, medicine, space and the environment. We have major projects underway in the areas of:

  • biointerfaces and interactions of biosystems for diagnostic / therapeutic medicine and nanomedicine;
  • materials processing for additive manufacturing;
  • physics in biology for biomimetic and neural network applications
  • novel plasma deposition and processing methods to create new materials;
  • carbon materials under extreme conditions
  • the development of thin film materials for application in the microelectronics and manufacturing industries; and
  • materials and processes for renewable and sustainable energy
  • building technologies for sustainable cities

Analytical services

We provide a number of high quality analysis methods for the creation and characterisation of thin film materials. Access to these methods and personnel highly skilled in their interpretation is open to outside users on a fee for service basis.

Interested researchers should contact the nominated academic staff member for advice about the availability and applicability of the equipment for the proposed experiment.

When emailing the nominated staff member please provide the following information:

  • your contact details / research group / school or details of your organisation
  • your research and why you want to have access to the equipment
  • an estimate of usage time required
  • your expertise in using the equipment.

The following analysis equipment is available:

X-ray photoelectron spectroscopy (XPS) can be used for investigating the surface chemistry of electrically conducting and non-conducting samples This technique has a sampling depth (sensitivity depth) of approximately 10 nm, i.e. the information is collected from the top 10 nm or so of the sample. XPS uses a soft X-ray beam to eject photoelectrons from the surface of a specimen. The energy of the photoelectrons depends on the element that released them and its chemical bonding environment. Surface analysis can be carried out by examining the energy distribution of the emitted photoelectrons. Not only are constituent elements identified in the spectrum but also their bonding conditions can be deduced. 

Our SPECS XPS [model XR 50 High Performance Twin Anode with Focus 500 Monochromator and PHOIBOS 150 MCD hemispherical analyzer] system is equipped with sample manipulation, enabling samples to be transferred to and from other experiments, especially to and from our SNMS system. Elemental composition can be measured with a sensitivity of up to 0.1 atomic %. Depth profiled measurements are also available.

Secondary Neutral Mass Spectrometry [SNMS] is a surface analysis technique complementary to XPS. A plasma is used to sputter etch the surface uniformly, releasing atoms from the sample. These atoms are ionised and their mass to charge ratio is analysed in a mass spectrometer. The mass spectrum is directly related to the composition of the surface under analysis. Detection limits of parts per million (ppm) can be achieved and unlike most other composition analysis methods, hydrogen can be analysed. Note that this technique is related to the more well-known secondary ion mass spectrometry technique [SIMS] but has the advantage that it is more sensitive since most of the material sputtered from a surface consists of neutral atoms rather than ions.

For further information on using this equipment for research please email Dr Behnam Akhavan or Dr Elena Kosobrodova.

FTIR detects absorptions due to the vibrational modes of a sample in the infrared region of the spectrum. Many chemical bonds have resonances in the infra-red. The fact that their characteristic absorptions are often sensitive to local chemical environments makes this a powerful method for analysis of chemical bonds in materials.

There are a number of ways in which we can accumulate spectra: 
* transmission spectroscopy;
* polarization spectroscopy (PIKE infrared polarizer); 
* reflection spectroscopy (PIKE variable angle specular reflectance accessory, angle of incident can varies from 30 to 80, different size of holes for samples);
* attenuated total reflection (ATR) spectroscopy 

Ge crystal, prism 45 degrees, multiple reflection (Harrick, Horizon)
Ge and Si hemisphere crystals, single reflection (Harrick, MVP 2)
Ge and Si hemisphere crystals in vacuumed attachment.

Transmission spectroscopy is useful if the sample transmits an infrared beam (for example, polymer films), while reflection and ATR can be carried out on any surface. Reflection and ATR measurements are also suitable when surface structures need to be resolved against those in the bulk.

Our FTIR system is a Digilab (model FTS7000) which measures absorption spectra in the wavenumber range 7000 cm^-1 to 250 cm^-1 with highest resolution of 0.09 cm^-1. It is fitted with sample transfer so that specimens can, if necessary, be transported from a synthesis chamber under a controlled atmosphere. For ATR spectroscopy, the sample is pressed against a germanium or silicon crystal that contains the infrared beam. The evanescent field from the crystal penetrates the specimen to depths of a few micrometers and is surface sensitive. 

Our latest research shows that FTIR techniques are useful to examine polymer surfaces for the presence of proteins and by examining the details of the resulting spectrum, it is possible to determine whether the protein has become unfolded.

For further information on using this equipment for research please email Dr Elena Kosobrodova or Dr Behnam Akhavan.

Electron beam evaporation

We have a range of techniques to deposit materials by physical and chemical vapour deposition processes. Electron beam evaporation is available in our Temescal/Simba2 system with a four hearth evaporator. In electron beam deposition a high voltage electron beam is directed in vacuum onto a crucible that contains the material to be evaporated. The material sublimes and forms a thin film coating on any exposed substrate.

Triple source cathodic arc coating system

The triple source cathodic arc coating system is a thin film deposition system used for plasma physics and materials research. Each cathode can be pulsed in sequence individually, allowing a high level of control over the depositing species flux ratios with each pulse delivering a sub-monolayer of material. The cathodes are centre triggered ensuring a repeatable flux of ions to the substrate over large numbers of pulses. Substrate biasing and heating up to 900C is possible. The design of the vacuum vessel permits several film and plasma diagnostics to be used in-situ including ellipsometry, plasma spectroscopy and stress measurements.

For further reading refer to:
Oates TWH, Pigott J, Mckenzie DR, Bilek MMM. Rev. Sci. Instrum. 2003;74: 4750
Rosén J, Ryves L, Persson POÅ, and Bilek MMM. J. Appl. Phys. 2007;101: 056101

For further information on using this equipment for research please email Marcela Bilek.

AJA multisource RF/DC sputtering system

The AJA ATC-1800 Thin Film Deposition System is a sputter coating system used for materials research and plasma studies. In the system, four sputtering targets are operated under computer control, allowing the deposition of complex multilayered and alloyed films with precise control of layer composition and thickness. The design of the vacuum vessel permits several film and plasma diagnostics to be used in-situ, including ellipsometry, plasma spectroscopy, and stress measurement. Sputtering power supplies operating in DC, pulsed DC, RF and HPPMS (High-power pulsed) modes are available. This provides the capability to deposit films of both conductive and insulating materials. The magnetrons accept 3" targets and are arranged in a tilted, confocal configuration, giving coatings with uniformity of better than +-2% over the entire substrate area.

The 4" diameter substrate holder allows substrate biasing and substrate heating to temperatures of 850 degrees Celsius. A sample load lock permits rapid throughput of samples. The vacuum system includes turbomolecular, cryogenic and sublimation pumps and can attain a base pressure of 1*10^-9 torr.

For further information on using this equipment for research please email Behnam Akhavan.

Our laboratory has a UV/visible/near IR dual-beam spectrophotometer (the Cary 5E) that is fitted with a V-W reflectance accessory. This equipment measures transmitted and reflected light from a sample of approximate size 10mm square. The wavelength range covered is approximately 200nm to 2600nm, i.e. the UV, visible and near infrared.

For further information on using this equipment please contact Dr Cenk Kocer by email.

Contact angles are measured in our Kruss contact angle instrument (DSA-10 MK2) or in our Biolin Scientific (Theta Optical) Tensiometers by analysis of a drop of liquid on the solid surface to be characterised. The contact angle of a water drop measures the hydrophobic/hydophilic character and when combined with another fluid can be used to extract the polar and dispersic components of surface energy. 

All together 4 different liquid drops with managed size (volume) of drops are available to measure. Kinetics of drop spreading, advancing and retreating contact angles can be measured with time. The software allows the use of different methods for drop shape analysis and calculation of surface energy and its components. A built-in database for different liquids gives great flexibility in terms of the method for surface energy analysis. 

For further information on using this equipment for research please email Dr Elena Kosobrodova or Dr Behnam Alhavan.

Stylus Surface Profilers can measure the surface roughness and thickness of thin films when an edge is created via masking. A vertical resolution of approximately 1nm is achievable. The profiler is useful for measuring film stress by means of a curvature measurement.

We have two profilometers. For our Tencor P11 please contact Dr Cenk Kocer. Our Dektak profilometer has the additional features of 3D surface mapping capability and built-in software for stress calculations

For further information on using this equipment for research please contact Dr Behnam Akhavan or Dr Elena Kosobrodova.

Infrared spectroscopic ellipsometer WOOLLAM WVASE-IR

Ellipsometry is a powerful technique for examining the optical properties of a surface. It measures the amplitude and the phase of light reflected from the surface and from this, the real and imaginary parts of the refractive index and dielectric constant can be extracted. 

Our JA Woollam M2000 instrument covers the visible and near infrared ranges, while our Woollam IR infrared ellipsometer covers the near and mid IR ranges.

WVase-IR is the spectroscopic ellipsometer to cover the spectral range from 333 to 5000 cm^-1. This is a combination of an optical ellipsometer and an infrared spectrometer (www.jawoollam.com). The WVase-IR can determine both n and k for materials in infrared diapason of wavelength. WVase-IR is perfect for thin films and bulk materials including dielectrics, semiconductors, polymers, and metals, where the capability to observe molecular vibrations is useful. It can be used for:

  • bulk substrates
  • phonon absorption - crystalline materials
  • optical constants (n and k , ε1 and ε2)
  • surface and interfacial layers
  • film thickness (single and multilayers)
  • doping concentration (resistivity)
  • material composition (alloy fraction)
  • free carrier absorption
  • chemical bonding - molecular vibrations
  • anisotropy - uniaxial and biaxial.

The spectral resolution is from 1 to 32 cm^-1. The angle of incidences of the probe beam can be varied from 26 to 90 degrees using a vertical sample mount. Temperature control (from room to 300C) is available. 

In recent research we have used the WVase-IR ellipsometer for vibrational analysis of a protein layer (5 nm) on the top of a carbonized polymer layer (2 nm) and have been able to resolve and characterise both layers. 

For further information on using this equipment for research please email Dr Elena Kosobradova or Dr Behnam Akhavan.

Temperature dependent electrical measurement system

This system provides the capability of assessing the electrical properties such as resistivity and the IV curve of thin films as a function of temperature. Electrical resistivity measurement is based on the Van der Pauw technique and it is capable of measuring resistivities ranging from 10-4 to 10 3 ohm cm. The temperature range covered is 30K to 380K.

For further information on using this equipment for research please email Professor David McKenzie.

Plasma immersion ion implantation (PIII)

Plasma immersion ion implantation (PIII) is a surface modification technique which extracts and accelerates ions from a plasma by applying a high voltage pulsed DC bias to the substrate or to a conducting cage placed around the material to be modified. The plasma is generated in a vacuum chamber with a helicon plasma source. 

Gaseous ions (hydrogen, nitrogen, oxygen, argon, neon) are available for implantation. The nominal pressure during the PIII process is from some to parts of mTorr. The energy of implanting ions varies from 1 keV to 20 keV. Pulse durations at 10-50 μSec can be applied at frequencies of 50-2000 Hz. Typical treatment fluencies are in the range of 10^14-10^17 ions/cm^2. 

For insulators eg glass, polymers,we use a metal mesh to eliminate surface charging effects. Often the sample is flat plate or film. However, complex shaped samples can be also treated. 

In recent research we have demonstrated the usefulness of PIII for improving adhesion, wettability, chemical activity, hardness and biocompatibility on polymer surfaces. 

For a detailed description of PIII method for polymers refer to A. Kondyurin and M. Bilek, Ion Beam Treatment of Polymers, in Application aspects from medicine to space, Elsevier, Oxford, 2008.

For further information on using this equipment for research please email Dr Elena Kosobrodova or Dr Behnam Akhavan.

Hiden EQP plasma diagnostic system

The Hiden system is an advanced plasma diagnostic tool with combined high transmission ion energy analyzer and quadrupole mass spectrometer, acquiring both mass spectra at specified ion energies and ion energy distributions of selected plasma ions.

For further information on using this equipment for research please email Professor Marcela Bilek or Professor David McKenzie.

Impact drop-test apparatus

The impact drop-test is used to measure the impact strength of structures. Various impactors can be used to impact a target surface, where the impact force can be obtained in situ. Using high speed photography the impact process and the failure of the target can be filmed and visualized. This apparatus is specifically designed for testing glass structures; nonetheless, other brittle materials can also be tested. Samples as large as 1m x 1m sheets of material can be accommodated.

For further information on using this equipment please contact Dr Cenk Kocer by email.

Residual gas analyser

Residual gas analysers are widely used in vacuum technology. This instrument is essentially a mass spectrometer designed for determining unknown species, and partial pressures of residual gases in a vacuum system. In each of the measurements, a mass scan of amu 1 to 100 is obtained to identify the released gas species. Then those identified gas species are selected to run a partial pressure trend graph, which displays the time dependence of outgassing of a specimen.

For further information on using this equipment for research please email Professor Marcela Bilek or Professor David McKenzie.

Contacts

Marcela M M Bilek

Professor of Applied Physics
Address
  • Room 407 Physics A28

David R McKenzie

Professor
Address
  • Room 441 Physics A28