Carrier mass measurements in degenerate indium nitride

Abstract

We present photoluminescence measurements under intense magnetic fields ($B$ up to 30 T) in $n$-doped indium nitride samples with carrier concentration ranging from about $7.5\ifmmode\times\else\texttimes\fi{}{10}^{17}\text{ }{\text{cm}}^{\ensuremath{-}3}$ to $5\ifmmode\times\else\texttimes\fi{}{10}^{18}\text{ }{\text{cm}}^{\ensuremath{-}3}$. The observation of transitions involving several Landau levels permits to determine the carrier-reduced mass $\ensuremath{\mu}$ around the $\ensuremath{\Gamma}$ point. Depending on the carrier concentration, we find $\ensuremath{\mu}$ ranging between $0.093{m}_{0}$ and $0.107{m}_{0}$ (${m}_{0}$ is the electron mass in vacuum). This finding poses a lower limit to the electron effective mass, whose unexpectedly large value $({m}_{e}\ensuremath{\ge}0.093{m}_{0})$ indicates that the sources of $n$ doping in InN perturb strongly the crystal conduction band near its minimum.