Chen Songsong, Liu Hongtao, Chen Fuhai, Zhou Kai, Xue Yunzhou
College of Mechatronics and Control Engineering, Shenzhen University, Nan-hai Ave 3688, Shenzhen 518060, China.
Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
ACS Nano. 2020 Sep 22;14(9):11473-11481. doi: 10.1021/acsnano.0c03863. Epub 2020 Sep 10.
Different from layered two-dimensional (2D) transition metal dichalcogenides (TMDs), iron dichalcogenides crystallize in the most common three-dimensional pyrite or marcasite structures. Layered iron dichalcogenides are rarely reported and little is known about their structures and properties. Here, layered hexagonal phase iron ditelluride FeTe (FeTe) nanocrystals are grown on mica by atmospheric pressure chemical vapor deposition (APCVD) method and are fully characterized by various methods. Like other 2D layered TMD materials, the FeTe nanoflakes exhibit regular hexagon, half hexagon, or triangle shapes with a controllable thickness of 6-95 nm and lateral length from a few to tens of micrometers. A simple and effective method is used to transfer the FeTe nanoflakes from the mica substrate onto any other substrates without quality deterioration by using polystyrene (PS) as a support polymer, which can also be operated in ethanol or ethylene glycol in a glovebox to avoid contact with water and air. Temperature-dependent electrical transport demonstrates that the FeTe nanoflake is a semiconductor with a variable range hopping (VRH) conduction, and its nonsaturated linear magnetoresistance (MR) reaches up to 10.4% under magnetic field of 9 T at 2 K, both probably due to its structure disorders. No signature of magnetic ordering is observed down to 2 K. The CVD growth of this layered FeTe represents an addition to the extensive library of 2D materials, particularly iron chalcogenides or alloys. Synthesis, properties, and even doping of phase pure FeTe call for further study in the future.
与层状二维（2D）过渡金属二硫属化物（TMDs）不同，二硫属化铁以最常见的三维黄铁矿或白铁矿结构结晶。层状二硫属化铁鲜有报道，人们对其结构和性质知之甚少。在此，通过常压化学气相沉积（APCVD）法在云母上生长出层状六方相二碲化铁FeTe（FeTe）纳米晶体，并采用多种方法对其进行了全面表征。与其他二维层状TMD材料一样，FeTe纳米片呈现出规则的六边形、半六边形或三角形，厚度可控，为6 - 95纳米，横向长度从几微米到几十微米不等。使用一种简单有效的方法，以聚苯乙烯（PS）作为支撑聚合物，可将FeTe纳米片从云母衬底转移到任何其他衬底上，且质量不会下降，该操作也可在手套箱中的乙醇或乙二醇中进行，以避免与水和空气接触。温度依赖的电输运表明，FeTe纳米片是一种具有变程跳跃（VRH）传导的半导体，在2 K、9 T磁场下其非饱和线性磁电阻（MR）高达10.4%，这两者可能都归因于其结构无序。在低至2 K时未观察到磁有序的迹象。这种层状FeTe的化学气相沉积生长为二维材料，特别是硫属化铁或合金的丰富文库增添了新成员。相纯FeTe的合成、性质乃至掺杂在未来都需要进一步研究。
