Carrier Mobility up to 106cm2V−1s

Diamond is hard: Carrier mobility in diamond is a key parameter for the development of future electronics and quantum devices, yet the low-field mobility of holes in ultrapure diamond is unknown, below 80 K or so. This study presents a time-of-flight technique using electron-beam-induced current to measure the velocities of electrons and holes as a function of temperature and electric field. A low-field mobility of (1.03$\ifmmode\pm\else\textpm\fi{}$0.05)$\ifmmode\times\else\texttimes\fi{}$10${}^{6}$ cm${}^{2}$ V${}^{\ensuremath{-}1}$ s${}^{\ensuremath{-}1}$ is measured for holes at 13 K, demonstrating that diamond is a suitable material for ballistic transport of charge carriers at a length scale of greater than 10 \ensuremath{\mu}m.