作　　者： (颜世莉）; (谢志坚）; (王磊）; (陈剑豪）;

机构地区： 北京大学物理学院,量子材料科学中心,北京100871

出　　处： 《中国科学：物理学、力学、天文学》 2017年第9期80-87,共8页

摘　　要： 本文利用三氧化钼(MoO_3)/金(Au)作为二硫化钼(MoS2)场效应晶体管的电极,得到了接触改善的N型二硫化钼场效应晶体管,并对其输运性质进行了变温测量.研究发现,将氧化钼作为在二硫化钼与金属电极之间的过渡层,可以很好地改善二硫化钼场效应器件的肖特基接触:对于2nm厚度的二硫化钼,其室温迁移率可达25cm2V^(–1)s^(–1),与没有三氧化钼接触的器件相比,室温迁移率提高了近16倍;对于8nm厚度的二硫化钼,其低温迁移率最高可达100cm^2V^(–1)s^(–1).优化后的电接触使得我们可以提取出二硫化钼器件本征的低温输运特性,并发现缺陷杂质对载流子的散射是影响器件输运性质的主要原因;其中在少层二硫化钼中,缺陷杂质的散射作用随着载流子浓度的增加、屏蔽能力的增强而减少.这种改善接触的方法同样适用于其他过渡金属硫族化合物. Molybdenum disulfide （MoS2）, a member of the transition-metal dichalcogenides （TMDs） family, is a semiconducting layered matierial consisting of two atomic layers of S atoms and Mo atoms. Comparing with semimetal graphene, its relatively large band gap makes MoS2 more suitable for applications in logic cricuit. Besides, strong spin orbit coupling and special symmetric structure give MoS： many intriguing physical and chemical properties. However, contacts between metals and MoS2 remain a critical issue which hinders not only the investigation of the intrinsic properties of MoS2 but also its applications. Therefore, it is urgent to find the technique that can improve the contact condition between metal and MoS2. In this work, using MoO3/Au as the electrode of MoS2 based field effect transistors （FETs）, we obtained N-type MoS2 FETs with improved contact conditions. The transport properties of these devices at different temperatures is also investigated. We demonstrated that the Schottky contact of the MoS2 FETs can be well improved by the interlayer MoO3 between MoS2 and metal electrodes： for device with 2 nm thick channel MoS2, the room temperature mobility can be as high as 25 cm2 V-~ s ~, 16 times higher than device without Mona contact; for device with 8 nm thick channel MoS2, the highest value of the low temperature mobility is as high as 100 cm2 V-~ s~. Therefore, we extracted the intrinsic low tempera^u＇e property of MoS2 FETs： the transport property of few layer MoS2 devices is dominated by the scattering of charge carriers from defect or charge traps; such scattering is weakened as the carrier density increases and screening is imt^roved. The techniaue demonstrated in this work can also be aonlied to other TMDs field effect devices.

关 键 词： 场效应晶体管 接触 纳米材料电输运