PMID- 28924327
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20191120
IS  - 0740-3224 (Print)
IS  - 1520-8540 (Electronic)
IS  - 0740-3224 (Linking)
VI  - 34
IP  - 7
DP  - 2017 Jul
TI  - Direct comparison of time-resolved Terahertz spectroscopy and Hall Van der Pauw 
      methods for measurement of carrier conductivity and mobility in bulk 
      semiconductors.
PG  - 1392-1406
LID - 10.1364/JOSAB.34.001392 [doi]
AB  - Charge carrier conductivity and mobility for various semiconductor wafers and 
      crystals were measured by ultrafast above bandgap, optically excited 
      Time-Resolved Terahertz Spectroscopy (TRTS) and Hall Van der Pauw contact methods 
      to directly compare these approaches and validate the use of the non-contact 
      optical approach for future materials and in-situ device analyses. Undoped and 
      doped silicon (Si) wafers with resistances varying over six orders of magnitude 
      were selected as model systems since contact Hall measurements are reliably made 
      on this material. Conductivity and mobility obtained at room temperature by 
      terahertz transmission and TRTS methods yields the sum of electron and hole 
      mobility which agree very well with either directly measured or literature values 
      for corresponding atomic and photo-doping densities. Careful evaluation of the 
      optically-generated TRTS frequency-dependent conductivity also shows it is 
      dominated by induced free-carrier absorption rather than small probe pulse phase 
      shifts, which is commonly ascribed to changes in the complex conductivity from 
      sample morphology and evaluation of carrier mobility by applying Drude scattering 
      models. Thus, in this work, the real-valued, frequency-averaged conductivity was 
      used to extract sample mobility without application of models. Examinations of 
      germanium (Ge), gallium arsenide (GaAs), gallium phosphide (GaP) and zinc 
      telluride (ZnTe) samples were also made to demonstrate the general applicability 
      of the TRTS method, even for materials that do not reliably make good contacts 
      (e.g., GaAs, GaP, ZnTe). For these cases, values for the sum of the electron and 
      hole mobility also compare very favorably to measured or available published 
      data.
FAU - Alberding, Brian G
AU  - Alberding BG
AD  - Radiation Physics Division, National Institute of Standards and Technology, 
      Gaithersburg, MD, 20899, USA.
FAU - Thurber, W Robert
AU  - Thurber WR
AD  - Engineering Physics Division, National Institute of Standards and Technology, 
      Gaithersburg, MD, 20899, USA.
FAU - Heilweil, Edwin J
AU  - Heilweil EJ
AD  - Radiation Physics Division, National Institute of Standards and Technology, 
      Gaithersburg, MD, 20899, USA.
LA  - eng
GR  - 9999-NIST/Intramural NIST DOC/United States
PT  - Journal Article
DEP - 20170612
PL  - United States
TA  - J Opt Soc Am B
JT  - Journal of the Optical Society of America. B, Optical physics
JID - 9880875
PMC - PMC5600209
MID - NIHMS899067
EDAT- 2017/09/20 06:00
MHDA- 2017/09/20 06:01
PMCR- 2018/07/01
CRDT- 2017/09/20 06:00
PHST- 2017/09/20 06:00 [entrez]
PHST- 2017/09/20 06:00 [pubmed]
PHST- 2017/09/20 06:01 [medline]
PHST- 2018/07/01 00:00 [pmc-release]
AID - 10.1364/JOSAB.34.001392 [doi]
PST - ppublish
SO  - J Opt Soc Am B. 2017 Jul;34(7):1392-1406. doi: 10.1364/JOSAB.34.001392. Epub 2017 
      Jun 12.