Laser Assisted Printing Of Metallic Compound Semiconductors

Additive manufacturing(or 3D printing)combines the advantages of information technology,automation and molding technologies to aim rapid prototype of arbitrary personalized digital 3D models.It is regarded as the representative technology for the coming Industry 4.0.Comparing with traditional subtractive manufacturing technics(casting,stamping and cutting),additive manufacturing is more cost-saving and time-saving and capable of one-step molding complicate 3D structures.Additive manufacturing has been very successful in printing metals,ceramics,plastics and glass as well as manufacturing aircraft components,personalized medical implants,industry design,education and fashion.However,the printable material categories are still very limited comparing to the thousands of material types that applied in industry.Therefore,it is very significant to develop new additive manufacturing methods to enrich the printable materials library.Metallic compound semiconductor is one of the most important material catagories in the information age.However,due to their various types,different growth conditions,high melting temperature and easy decomposition properties,and also the requirements of high purity and high crystallinity,it is still a challenge to realize the additive manufacturing of metallic compound semiconductors.Herein,we develop a polymer-assisted deposition method involving the mechanism of thermal induced copolymerization and curing of reducing sugar and polyethyleneimine to realize a laser-assisted printing of metallic compounds semiconductor.It is worthy of noting that the printing semiconductor materials include metal oxides,metal sulfides,metal nitrides,and functional materials including super conductor,magnetic and ferroelectric materials,glassy graphene and typical electoral devices of diode.In this work,polyethyleneimine is applied for metal ions carrier,and infrared IR laser is utilized to achieve printing and patterning of precursors through triggering the crosslinking of polyethyleneimine and sugar.Annealing process contributes to in-situ growth and crystallization of metal ions while removing organic components such as sugar and polyethyleneimine.The specific research contents include the following four parts:1.The copolymerization and curing mechanism for polyethyleneimine and reducing sugar.It is found that the water soluble precursor film consisting of reducing sugar(glucose or maltose)and polyethyleneimine is curing and gets water insoluble immediately through heating at 120 ? and above.Nevertheless,this thermal induced curing phenomenon does not happen through heating reducing sugar or polyethyleneimine.The crosslinking and curing process of reducing sugar with polyethyleneimine was preliminarily revealed by thermo gravimetric analysis,photoelectron spectroscopy,ultraviolet-visible absorption spectroscopy and X-ray near-edge absorption spectroscopy.2.Laser printing of reduce sugar and polyethyleneimine.Based on the thermal induced copolymerization and curing of polyethyleneimine with reducing sugar,IR infrared laser enables the selective area curing and printing of the precursor film and perform.An efficient printing speed as high as 1500mm/s is explored after analyzing the quality and characteristics of printed patterns using different molecular weights of polyethyleneimine,different laser wavelengths,different laser scanning speeds and different laser output powers,and the functional parameter range of laser-assisted printing.3.Laser assisted printing metallic compound semiconductors.As water-soluble precursor,metal ions were coordinated to polyethyleneimine and mix with maltose to prepare an aqueous solution for laser printing.During the thermal treatment,metal ions precursor is readily to grow metallic compounds along with the removal of organic components in the precursor,achieving good crystallinity and high purity of metallic compounds.Utilizing this route,we have realized the printing of metallic compound semiconductor materials including metal oxides,metal sulfides,and metal nitrides,and even the printing of superconducting material,magnetic material and ferroelectric material as well as printing the P/N junction.4.Laser-assisted printing of graphene film.Using glucose and polyethyleneimine as precursor,a new kind of carbon called "glassy graphene" thin film is discovered with a structure between the glassy carbon and the graphene film.The glassy graphene thin film has not only ultra-smooth,uniform and dense structure,but also shows excellent optical and electrical properties close to the graphene film.Furthermore,it performs the excellent mechanical stability,chemical stability and thermal stability.To fabricate the diversity of structures,the laser-assisted printing method is attempted to print the pattern of glassy graphene thin film.Alike the glassy graphen,the desirable patterns of the printed thin films are demonstrated the flexibility,reliability,and transferablility.It is promising to apply for the flexible electronic circuits.This thesis has proved the feasibility and reliability of laser-assisted metallic compound printing.It greatly expands the library of printable materials for additive manufacturing.This new kind of the additive manufacturing is very efficient and universal to 2D/3D fabrication of metal compound semiconductors.This strategy enriches the additive manufacturing's applications including printing of semiconductor devices electronic circuits and establishes a platform for potential applications of 3D printing in the fields of solar cells,energy storage batteries,electro catalysis and micro-nano optical devices.