Mid-infrared optical Hall effect measurements are used to determine the free charge carrier parameters of an unintentionally doped wurtzite-structure c-plane oriented In0.33Ga0.67N epitaxial layer. Room temperature electron effective mass parameters of m⊥∗=(0.205±0.013) m0 and m∥∗=(0.204±0.016) m0 for polarization perpendicular and parallel to the c-axis, respectively, were determined. The free electron concentration was obtained as (1.7 ± 0.2) × 1019 cm-3. Within our uncertainty limits, we detect no anisotropy for the electron effective mass parameter and we estimate the upper limit of the possible effective mass anisotropy as 7%. We discuss the influence of conduction band nonparabolicity on the electron effective mass parameter as a function of In content. The effective mass parameter is consistent with a linear interpolation scheme between the conduction band mass parameters in GaN and InN when the strong nonparabolicity in InN is included. The In0.33Ga0.67N electron mobility parameter was found to be anisotropic, supporting previous experimental findings for wurtzite-structure GaN, InN, and AlxGa1-xN epitaxial layers with c-plane growth orientation.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)