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Electron effective mass in GaN revisited : New insights from terahertz and mid-infrared optical Hall effect

Armakavicius, Nerijus ; Knight, Sean ; Kühne, Philipp ; Stanishev, Vallery ; Tran, Dat Q. ; Richter, Steffen LU ; Papamichail, Alexis ; Stokey, Megan ; Sorensen, Preston and Kilic, Ufuk , et al. (2024) In APL Materials 12(2).
Abstract

Electron effective mass is a fundamental material parameter defining the free charge carrier transport properties, but it is very challenging to be experimentally determined at high temperatures relevant to device operation. In this work, we obtain the electron effective mass parameters in a Si-doped GaN bulk substrate and epitaxial layers from terahertz (THz) and mid-infrared (MIR) optical Hall effect (OHE) measurements in the temperature range of 38-340 K. The OHE data are analyzed using the well-accepted Drude model to account for the free charge carrier contributions. A strong temperature dependence of the electron effective mass parameter in both bulk and epitaxial GaN with values ranging from (0.18 ± 0.02) m0 to (0.34 ±... (More)

Electron effective mass is a fundamental material parameter defining the free charge carrier transport properties, but it is very challenging to be experimentally determined at high temperatures relevant to device operation. In this work, we obtain the electron effective mass parameters in a Si-doped GaN bulk substrate and epitaxial layers from terahertz (THz) and mid-infrared (MIR) optical Hall effect (OHE) measurements in the temperature range of 38-340 K. The OHE data are analyzed using the well-accepted Drude model to account for the free charge carrier contributions. A strong temperature dependence of the electron effective mass parameter in both bulk and epitaxial GaN with values ranging from (0.18 ± 0.02) m0 to (0.34 ± 0.01) m0 at a low temperature (38 K) and room temperature, respectively, is obtained from the THz OHE analysis. The observed effective mass enhancement with temperature is evaluated and discussed in view of conduction band nonparabolicity, polaron effect, strain, and deviations from the classical Drude behavior. On the other hand, the electron effective mass parameter determined by MIR OHE is found to be temperature independent with a value of (0.200 ± 0.002) m0. A possible explanation for the different findings from THz OHE and MIR OHE is proposed.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
APL Materials
volume
12
issue
2
article number
021114
publisher
American Institute of Physics (AIP)
external identifiers
  • scopus:85184994696
ISSN
2166-532X
DOI
10.1063/5.0176188
language
English
LU publication?
yes
id
e1cbcf5f-8228-45d4-936c-49ebc2fcf9b9
date added to LUP
2024-03-12 13:31:37
date last changed
2024-03-12 13:33:05
@article{e1cbcf5f-8228-45d4-936c-49ebc2fcf9b9,
  abstract     = {{<p>Electron effective mass is a fundamental material parameter defining the free charge carrier transport properties, but it is very challenging to be experimentally determined at high temperatures relevant to device operation. In this work, we obtain the electron effective mass parameters in a Si-doped GaN bulk substrate and epitaxial layers from terahertz (THz) and mid-infrared (MIR) optical Hall effect (OHE) measurements in the temperature range of 38-340 K. The OHE data are analyzed using the well-accepted Drude model to account for the free charge carrier contributions. A strong temperature dependence of the electron effective mass parameter in both bulk and epitaxial GaN with values ranging from (0.18 ± 0.02) m<sub>0</sub> to (0.34 ± 0.01) m<sub>0</sub> at a low temperature (38 K) and room temperature, respectively, is obtained from the THz OHE analysis. The observed effective mass enhancement with temperature is evaluated and discussed in view of conduction band nonparabolicity, polaron effect, strain, and deviations from the classical Drude behavior. On the other hand, the electron effective mass parameter determined by MIR OHE is found to be temperature independent with a value of (0.200 ± 0.002) m<sub>0</sub>. A possible explanation for the different findings from THz OHE and MIR OHE is proposed.</p>}},
  author       = {{Armakavicius, Nerijus and Knight, Sean and Kühne, Philipp and Stanishev, Vallery and Tran, Dat Q. and Richter, Steffen and Papamichail, Alexis and Stokey, Megan and Sorensen, Preston and Kilic, Ufuk and Schubert, Mathias and Paskov, Plamen P. and Darakchieva, Vanya}},
  issn         = {{2166-532X}},
  language     = {{eng}},
  month        = {{02}},
  number       = {{2}},
  publisher    = {{American Institute of Physics (AIP)}},
  series       = {{APL Materials}},
  title        = {{Electron effective mass in GaN revisited : New insights from terahertz and mid-infrared optical Hall effect}},
  url          = {{http://dx.doi.org/10.1063/5.0176188}},
  doi          = {{10.1063/5.0176188}},
  volume       = {{12}},
  year         = {{2024}},
}