Facilities

Fourier Transform Infrared spectroscopy (FT-IR)

FT-IR VERTEX 80v + Hyperion 2000

This facility was realized through a Hercules-1 project: FT-IMAGER, a wide-range multi-purpose Fourier-Transform Infrared facility for Materials, Archaeological and GEological Research. Information on the consortium behind this project and recent research results can be found on this site.

Basic instruments

  • BRUKER Vertex 80v vacuum wide-range multi-purpose FT-IR spectrometer, with spectral range between 15000 and 10 cm-1 (near- to far-IR)
  • Hyperion 2000 microscope in the near, mid and far IR

Peripheral equipment

  • Liquid helium cryostats for mid and far IR region: contact gas and cold finger
  • Home-built vacuum sample compartment for photoluminescence extension

Measurement modes

  • Transmission – Specular Reflection - Attenuated total reflection (ATR)
  • Photothermal ionization spectroscopy (PTIS)
  • Photoluminescence

Recent publications

Deep level transient spectroscopy (DLTS)

The following services with different measurement modes are possible for deep level transient spectroscopy.

Basic instruments

  • PhysTech Fourier Transform DLTS equipped with liquid He/liquid N2 crystats (4-600K) and Leybold temperature controller
  • Agilent fast pulse generator (pulse length >1 ns) for fast electrical filling pulses
  • Laser diodes (900 nm and 1500 nm) for optical filling pulses

Measurement modes

  • DLTS: classical capacitance DLTS using electrical pulse
  • CC-DLTS: constant capacitance DLTS
  • ODLTS: capacitance DLTS using optical pulse
  • CDLTS: current DLTS using optical or electrical pulse
  • QDLTS: charge DLTS

Current/recent research topics with selected papers

Semiconductor/insulator interface defects

Defects in thin-film solar cell materials

Extended defects related with epitaxial growth

Transition metal impurities in group IV semiconductors

Hall - Van der Pauw measurements

The Van der Pauw method makes it possible to precisely determine the electrical resistivity of a material by means of 4 contact points. Two contact points apply a well known current to the material, the other two measure the voltage across the material. This technique has the advantage to cancel out contact resistance on the measurement result. The same setup could also be used to measure Hall voltage.

Hall - Van der Pauw

Minority carrier lifetime measurements

The lifetime of minority charge carriers can be measured using contact methods (photoconductivity decay via electric resistance measurements), or using non-contact methods (photoconductivity decay measured by transient microwave reflection).

Sample Preparation

Thermal annealing is possible with the Carbolite programmable oven

carbolite oven
carbolite oven

 

carbolite oven detail
carbolite oven detail

All requests for DLTS and FTIR measurements may be addressed directly to and will be evaluated on an individual basis.