Fabrication And Performance Of Heterojunction Optoelectronic Devices Based On Two-dimensional Chalcogenide Heterojunction

Since two-dimensional graphene materials were first reported in 2004,which become a milestone in the field of two-dimensional materials.Since then,more research has been conducted on two-dimensional materials.Although graphene has excellent properties,its zero bandgap hinders its further development,so some scientists have turned their attention to the growth and application of other two-dimensional layered materials.Among them,transition metal chalcones(TMDs)are attractive because of their advantages such as adjustable band gap with film thickness,fast carrier migration speed and large area growth.However,the research on TMDs was not comprehensive,the chemical vapor deposition(CVD)growth process needs to be further optimized,and the types of heterojunctions need to be further explored.In this work,by introducing the concept of confine-spaced,the influence of growth parameters on the growth of MS₂(M=W,Mo)material was systematically studied.Besides,it is very important to explore the optical properties of TMDs and combining organic semiconductor materials to construct heterojunctions through van der Waals force.Because of the instability of organic materials in the air,the large-scale synthesis of materials had become a challenge.The spin-coating method was prepared to fabricate inorganic-organic heterostructure based on inorganic materials.Focus on the research on the optical properties of heterostructures,and achieve the research goals of controllable preparation and optical performance explore of heterostructures.It has high scientific research value for the development of inorganic-organic heterojunction.The specific research content was as follows.1.The effect of experimental conditions on the nucleation and structure morphology of MS₂ films was systematically studied.The controllable experimental technology of preparing single-layer,few-layer,and multi-layer WS₂ thin film materials has been mastered.The final determination to obtain a large area,monolayer,high crystalline quality WS₂ process is as follows:the growth time is 3 minutes,the distance between S source and the substrate is 20 cm,the heating temperature of WO₃ is 860?,and the ratio of WO₃ to S source is about 1/60.The characterization of single-layer,few-layer and multi-layer WS₂materials was studied.In the experiment,we used this set of processes to prepare MoS₂.Considering the low temperature required to grow MoS₂,the heating temperature of MoO₃is adjusted to 800?,and the other growth conditions remain unchanged.Monolayer MoS₂films with the size of a single side triangle of 300?m were prepared,which proved the stability of the process.2.The photoetching process was studied,and a double-layer photoetching process was finally determined for the fabrication of the WS₂ field-effect transistor(FET),the influence of optical power and voltage on the performance of the device were systematically studied.The electron mobility of the device was as high as 26.93 cm²V^-1S^-1,which was higher than the previously reported WS₂ film grown by CVD.Besides,the device cycle stability was excellent.On this basis,the WS₂-PCE10 inorganic-organic heterojunction was prepared.Through OM,SEM,Raman,and UV-vis measurement characterization,it was proved that PCE10 had high film formation quality and formed a good inorganic-organic heterojunction interface.Compared to the monolayer WS₂ film device,the photocurrent of the heterojunction device showed three orders of magnitude improvement.The heterojunction device was stored in a natural environment for 6 months,and its performance remained the same,which proved that the device was extremely stable.