Anisotropy of effective electron masses in highly doped nonpolar GaN

作者：Feneberg Martin^*; Lange Karsten; Lidig Christian; Wieneke Matthias; Witte Hartmut; Blaesing Juergen; Dadgar Armin; Krost Alois; Goldhahn Ruediger

来源：Applied Physics Letters, 2013, 103(23): 232104.

DOI：10.1063/1.4840055

The anisotropic effective electron masses in wurtzite GaN are determined by generalized infrared spectroscopic ellipsometry. Nonpolar (11 (2) over bar0) oriented thin films allow accessing both effective masses, m(perpendicular to)* and m(parallel to)*, by determining the screened plasma frequencies. A n-type doping range up to 1.7 x 10(20) cm(-3) is investigated. The effective mass ratio m(perpendicular to)m(parallel to)* is obtained with highest accuracy and is found to be 1.11 independent on electron concentration up to 1.2 x 10(20) cm(-3). For higher electron concentrations, the conduction band non-parabolicity is mirrored in changes. Absolute values for effective electron masses depend on additional input of carrier concentrations determined by Hall effect measurements. We obtain m(perpendicular to)* = (0.239 +/- 0.004)m(0) and m(parallel to)* = (0.216 +/- 0.003)m(0) for the parabolic range of the GaN conduction band. Our data are indication of a parabolic GaN conduction band up to an energy of approximately 400 meV above the conduction band minimum.

• 出版日期2013-12-2