Preparation Of Lead-Based Piezoelectric Materials And Its Transistor Device Research

Piezoelectric materials mainly include piezoelectric ceramics,piezoelectric single crystals,piezoelectric polymers,piezoelectric thin films,and piezoelectric composite materials.At present,the most widely used is lead-based piezoelectric ceramics,such as PZT series.In recent years,lead-based piezoelectric single crystals have received great attention for their excellent piezoelectric performance.The research work of this article includes two parts:the growth of a new relaxation piezoelectric single crystal PZNT and the fabrication of temperature and pressure bimodal sensor based on piezoelectric materials.In the first chapter,we briefly introduce various piezoelectric materials and their applications,comb the development history of piezoelectric materials,especially lead-based piezoelectric materials;then describe the development history of organic thin film transistors(OTFTs)and the four basic types of OTFT device structures:top grid bottom contact structure,top grid top contact structure,bottom grid top contact structure and bottom grid bottom contact structure.In the second chapter,we take the new relaxation piezoelectric single crystal PZNT as the research object and summarize the literatures,including the growth techniques,physical properties and applications of the new relaxation piezoelectric single crystals.The solid phase growth process is used to explore the new growth approach of PZNT crystals.However,this growth method is too difficult,and only some PZNT particles were obtained.Altnatively,we tried to grow PZNT crystals by the flux-Bridgman method.Optimizing the growth parameters,such as flux ratio,growth temperature,growth rate and post-annealing process,we obtained some centimeter-level single crystals.As-grown crystals show pale-yellow and transparent,and the ferroelectric properties are measured.In Chapter three,based on the working principle of OTFT,the temperature and pressure bimodal sensor was designed for the first time on PZT piezoelectric ceramics.The mobility of the prepared transistor reaches 4.81×10-3 cm2 V-1s-1,the temperature sensitivity of the device between 20-100℃ is significantly improved,and it is expected to have important application potential in the field of optical switching.Innitially,we aimed to grow PZNT crystals and fabricated OTFT devices on it.However,it is too difficult to grow PZNT crystals by the solid phase growth process.At the same time,we studied the fabrication of OTFT devices on PZT ceramics.The bimodal sensor developed for the first time using ceramics has shown good results.In the future,we will continue to develop bimodal sensors on PZNT crystals with more excellent piezoelectric performance,which may have better sensitivity,miniaturization and other aspects of the device.