Ni,Fe离子掺杂对Ge-Sb-Se薄膜的结构与性能影响研究

Effect of Ni, Fe-doping on the structure and properties of Ge-Sb-Se thin films

采用低温烧结靶材,以电子束蒸发方法制备了掺Fe和掺Ni的Ge-Sb-Se薄膜,所制备的薄膜均为p型半导体.用AFM,UV-VIS,Hall和阻抗分析仪研究了薄膜的形貌、结构和性能.研究表明薄膜形成时的成膜离子活性大、掺杂元素与系统本征元素电负性间差值小以及一定的热处理后,薄膜的网络结构相对较完整,网络畸变较小,缺陷也较少.掺杂Fe,Ni既可参与Ge-Sb-Se薄膜成键,影响网络结构的完整性;也会在费米能级附近引入缺陷态密度,增加了对载流子跃迁的陷阱作用.与Fe掺杂相比,Ni掺杂使薄膜具有较完整的网络结构,较低的中性悬挂键浓度和在交变电场下可具有较少的极化子产生,相应粗糙度较小、光学带隙较宽、载流子迁移率较高、载流子浓度较低和薄膜介电损耗较小.

Fe, Ni doped Ge-Sb-Se thin films are grown by electron-beam evaporation with targets sintered at low temperature, and show p-typed in conducting status. Investigated by AFM, UV-VIS, Hall and Impedance Analyzer, we observed that thin films have a more perfect network and less defects if the doped ion has a higher activity and smaller electronegative difference with the system elements, or the films are annealed. Fe and Ni doped in Ge-Sb-Se system not only take part in binding and affect the network perfection but also introduced defects near Fermi energy. Thin films doped with Ni have a more perfect network, lower neutron-hanging binding concentration and less pelarons produced under AC electric field compared with Fe doped thin films, thus have smaller roughness, larger optical band gap, higher cartier mobility, lower cartier concentration and smaller dielectric loss.