Contact-free charge carrier density determination of doped sub-μm thin cubic GaN layers with terahertz time-domain spectroscopy

@misc{hennig2026contactfree,
  title = {{Contact-free charge carrier density determination of doped sub-μm thin cubic GaN layers with terahertz time-domain spectroscopy}},
  author = {Joshua Hennig and Mario F. Zscherp and Silas A. Jentsch and Daniel Anders and Jörg Schörmann and Till Fuchs and Anja Henss and Sangam Chatterjee and Christian Röder and Franziska C. Beyer and Christina Jörg and Joachim Jonuscheit and Georg von Freymann and Daniel Molter},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.40142},
  eprint = {2610.40142},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.40142},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Contact-free charge carrier density determination of doped sub-μm thin cubic GaN layers with terahertz time-domain spectroscopy
AU  - Joshua Hennig
AU  - Mario F. Zscherp
AU  - Silas A. Jentsch
AU  - Daniel Anders
AU  - Jörg Schörmann
AU  - Till Fuchs
AU  - Anja Henss
AU  - Sangam Chatterjee
AU  - Christian Röder
AU  - Franziska C. Beyer
AU  - Christina Jörg
AU  - Joachim Jonuscheit
AU  - Georg von Freymann
AU  - Daniel Molter
PY  - 2026
DA  - 2026/10/29
PB  - arXiv
DO  - 10.48550/arxiv.2610.40142
UR  - https://arxiv.org/abs/2610.40142
AB  - As cubic GaN is a promising material for optoelectronic applications, its layers need to be precisely doped to realize the desired properties. While contact-based methods are established to measure the realized charge carrier density, contact-free techniques are more advantageous for this purpose. We show terahertz time-domain spectroscopy measurements of cubic GaN layers with thicknesses between 0.6 μm and 2 μm with doping densities in the range from 10^18 cm^−3 to 10^20 cm^−3. From these measurements, we determine the charge carrier densities and verify the results with time-of-flight secondary-ion mass spectrometry measurements. The results are in accordance with simulations of the doping ranges which the technique is expected to be sensitive in. In preparation for the terahertz time-domain spectroscopy measurements, we validated the layer thicknesses by Fourier-transform infrared spectroscopy measurements. With this, a wide range of doped cubic GaN samples can be addressed by optical methods. In the future, these techniques could allow for a fast and non-destructive characterization of GaN layers, right after or even during the growth process.
ER  -