Electrical scattering mechanism evolution in un-doped and halogen-doped Bi 2 O 2 Se single crystals

作者：Lu Xu, Ye-Cheng Luo, Yang‐Yang Lv, Yanyan Zhang, Yizhang Wu, Shu-Hua Yao, Jian Zhou, Yan-Feng Chen, Yan-Feng Chen · 发表于：Journal of Physics Condensed Matter · 年份：2020 · DOI：10.1088/1361-648x/ab913f · 被引用次数：5 · 研究领域：2D Materials and Applications、Topological Materials and Phenomena、Advanced Thermoelectric Materials and Devices

Abstract Recently the layered oxide semiconductor Bi 2 O 2 Se was hotly explored for its ultrahigh mobility and ultrafast photo-response whose physical origins need to be further explored or elucidated. Here, we have grown halogen (Cl, Br, I) doped and un-doped Bi 2 O 2 Se single crystals by a melt-solidification method. Comparative electrical transport characterizations and detailed data-analysis substantiate that the electron–electron scattering is the major source of resistivity in un-doped Bi 2 O 2 Se crystals; however, in halogen-doped Bi 2 O 2 Se crystals, electron–electron scattering is only effective at low temperature (<60 K) and subsequently electron–phonon-interaction scattering is dominated to resistivity. Hall measurement and analysis show that electron concentration of halogen-doped Bi 2 O 2 Se (∼10 20 cm −3 ) is one-order higher than un-doped one (∼10 19 cm −3 ), but the carrier mobility of halogen-doped Bi 2 O 2 Se at 2 K (∼10 2 cm 2 V −1 s −1 ) is reduced by more than two orders than un-doped ones (∼10 4 cm 2 V −1 s −1 ). Three kinds of relaxation time (due to the impurity scattering, electron–electron scattering and electron–phonon scattering), calculated by linear-response theory and electron-/phonon-dispersion, are in agreement with experimental results quantitatively. The scattering mechanism evolution from sole electron–electron scattering (un-doped Bi 2 O 2 Se) to electron–phonon scattering (doped Bi 2 O 2 Se) at high temperature (>60 K) is attrib...