Study On The New Structure And Device Of Two-dimensional Nano-semiconductor Material

In the past decade,two-dimensional materials have attracted the attention of researchers because of their remarkable properties.Two-dimensional atomic crystal materials,referred to as two-dimensional materials,namely a single layer or a few atomic layer thickness of two-dimensional crystal materials,whose thickness on the atomic scale,such ultra-thin structure makes two-dimensional materials show many unprecedented unique physical and chemical properties,quickly become a hotspot of scientific research.And in the field of microelectronic sensor application potential is infinite.The most representative two-dimensional nanomaterials are non-graphene materials.Graphene(GR)is a promising chemical sensing material due to its 2D conjugated structure,large specific surface area,low electrical noise and high sensitivity to electrical disturbances.However,because graphene is porous,it is brittle,it becomes tough after functionalization,and individual graphene has poor electrical conductivity due to its zero-band gap.In order to compensate for this shortcoming,researchers unremitting study found:the transition metal chalcogenide(TMDC)two-dimensional atomic crystal materials,this kind of graphene material shows many graphene does not have the physical properties,many studies have shown that the transistor,light detector,gas sensor,photovoltaic battery has high application prospect.In this paper,the controllable structure preparation of two-dimensional atomic crystal materials and its comprehensive performance of optical and gas sensitive detection are studied.The growth of two-dimensional atomic crystal materials of graphene and molybdenum disulfide,as well as the characteristics and applications of photoelectric and gas sensitive films based on the special structure of graphene and molybdenum disulfide atomic crystal are mainly studied.Important progress has been made in the following areas:(1)Chemical vapor deposition(CVD)technique was used to synthesize high-quality,large-area two-dimensional MoS₂ nano-walls on SiO₂ substrates quickly and conveniently.A high-performance photodetector based on MoS₂ nano-wall for measuring different operating temperatures.The optical responsiveness and specific detection rate of the obtained optical detector are stable at 200?,and the maximum optical responsiveness and specific detection rate are up to 104.3 m A/W and 6.24×10¹²Jones.At the same time,the response and recovery time of the photodetector is reduced to 1ms.The results show that the new vertical nanosheet structure greatly improves the performance of the sensor because of its large specific surface area.(2)A transparent flexible field effect transistor(FET)dual function sensor with MoS₂ as optical channel and gas channel is fabricated.Under light conditions,the flexible devices based on MoS₂ films obtained a high response of 2512%at room temperature and good recovery.In addition,the MoS₂ nano-wall also exhibits good photosensitive properties,such as fast light switching time(0.05 ms),high current response rate and high specific detection rate.The results show that the MoS₂ FET transistor sensor device is a promising candidate device for photoelectric detector,and it is also a very instructive gas sensor,which provides a strategy for the design of sensor parts with dual functions.(3)Using H₂/CH₄ gas as precursor,the structure of large-area porous vertical graphene nanosheets,also known as GNWs(graphene nanowalls),was directly prepared by plasma enhanced chemical vapor deposition(PECVD)technique as sensing layer.The newly prepared GNWs sensor has higher responsiveness and selectivity to NH₃gas at room temperature,and lower detection limit.Charge transfer is the main sensing mechanism of GNWs sensor.The two-dimensional graphene nanosheets with high specific surface area,large number of defects and small grain size with vertical three-dimensional structure have excellent sensing performance.