On the diffusion of free carriers in β-rhombohedral boron

摘要: Abstract To determine the diffusion of untrapped carriers in β-rhombohedral boron, we constructed a feedback pico-ammeter based on pulse integration technique. This enabled measuring deviations from bias 109 Ω sample order 1 nA with 0.7 ms time resolution. For first time, obtained drift velocity optically generated electron–hole pairs 106(20) cm s−1 yielding for band-determined coefficient D = 1 2 ( 4 ) cm s - and carrier mobility μ ambipolar 5 6 0 V . Fitting Fick's second law to measured trap-determined dispersion yields * 0.0 3 0.28(10) cm2 s−1 at 260 340 K, respectively. The thermal activation energy 0.18 eV agrees well-known trapping levels boron.