Transition metal dichalcogenides(TMDCs) belong to a subgroup of two-dimensional(2 D) materials which usually possess thickness-dependent band structures and semiconducting properties. Therefore, for TMDCs to be widely...Transition metal dichalcogenides(TMDCs) belong to a subgroup of two-dimensional(2 D) materials which usually possess thickness-dependent band structures and semiconducting properties. Therefore, for TMDCs to be widely used in electronic and optoelectronic applications, two critical issues need to be addressed, which are thickness-controllable fabrication and doping modulation of TMDCs. In this work, we successfully obtained monolayer WS2 and achieved its efficient doping by chemical vapor deposition and chemical doping, respectively. The n-and p-type dopings of the monolayer WS2 were achieved by drop coating electron donor and acceptor solutions of triphenylphosphine(PPh3) and gold chloride(AuCl_3), respectively, on the surface, which donates and captures electrons to/from the WS2 surface through charge transfer, respectively. Both doping effects were investigated in terms of the electrical properties of the fabricated field effect transistors. After chemical doping, the calculated mobility and density of electrons/holes are around 74.6/39.5 cm^2 · V^(-1) ·s^(-1)and 1.0 x 10^(12)/4.2 x 10^(11) cm^(-2), respectively. Moreover, we fabricated a lateral WS2 p-n homojunction consisting of nondoped n-type and p-doped p-type regions, which showed great potential for photodetection with a response time of 1.5 s and responsivity of 5.8 A/W at V_G = 0 V and V_D = 1 V under 532 nm light illumination.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.21405109)Seed Foundation of State Key Laboratory of Precision Measurement Technology and Instruments,China(Grant No.1710)
文摘Transition metal dichalcogenides(TMDCs) belong to a subgroup of two-dimensional(2 D) materials which usually possess thickness-dependent band structures and semiconducting properties. Therefore, for TMDCs to be widely used in electronic and optoelectronic applications, two critical issues need to be addressed, which are thickness-controllable fabrication and doping modulation of TMDCs. In this work, we successfully obtained monolayer WS2 and achieved its efficient doping by chemical vapor deposition and chemical doping, respectively. The n-and p-type dopings of the monolayer WS2 were achieved by drop coating electron donor and acceptor solutions of triphenylphosphine(PPh3) and gold chloride(AuCl_3), respectively, on the surface, which donates and captures electrons to/from the WS2 surface through charge transfer, respectively. Both doping effects were investigated in terms of the electrical properties of the fabricated field effect transistors. After chemical doping, the calculated mobility and density of electrons/holes are around 74.6/39.5 cm^2 · V^(-1) ·s^(-1)and 1.0 x 10^(12)/4.2 x 10^(11) cm^(-2), respectively. Moreover, we fabricated a lateral WS2 p-n homojunction consisting of nondoped n-type and p-doped p-type regions, which showed great potential for photodetection with a response time of 1.5 s and responsivity of 5.8 A/W at V_G = 0 V and V_D = 1 V under 532 nm light illumination.
