,Interaction between laser and material,满宝元,山东师范大学物理与电子科学学院,1. Laser Technology and Applications 2. Laser-material interaction,Study on the properties of plasmas produced by pulsed laser ablation of solid materials Pulsed Laser Deposition (PLD) Surface modification of polymer by a pulsed laser Interaction of laser and atome, molecule The interaction of a laser pulse with clusters.,Interaction between laser and materials (part II),Study on the properties of plasmas produced by pulsed laser ablation of solid materials,CONTENT : 1. INTRODUCTION 2. EXPERIMENTAL SETUP 3. EXPERIMENTAL RESULTS AND DISCUSSION 4. CONCLUTUION,1. INTRODUCTION Plasma emission: time-space resolved spectroscopy Sample :Al, Cu, Ti, Fe, GaAs, Si, HgCdTe Principal research content: 1) Heating and damage of surface, including absorption, melting, heat-conduction, damage-threshold, etching-rate etc. 2) Production and emission of plasma, including the excitation and ionization of atom, emission intensity, life etc.,3) Line-broadening and shift of emission line 4) Electron temperature and density. 5) The expanding dynamics of the plasma. Give model in theory. 6) Impulse coupling process of interaction between laser and materials. 7) Ambient impact 8) Laser parameter impact.,2. EXPERIMENTAL SETUPInstruments: (1) Nd:YAG pulsed laser device: A duration of 10ns, a wavelength of 1.064 m, and the maximum laser energy was 1J. (2) Optical Multichannel Analyzer (OMA III). (3) Others, such as Digital Oscilloscope (Tektronix TDS 620A), photoelectric diode, boxcar etc.,(a),(a),3. Experimental results,P=105 Pa,GaAs Sample,(c),(c),P=5 Pa,P=105 Pa,P=5 Pa,The time of-flight curves of Ga I 403.3 nm,Monte-Carlo Trim 98,P=5Pa,P=105Pa,HgCdTe Sample,TABLE : The average velocities of the excited atoms at different positions and pressures(m/s),The blast (shock) wave model Considering ejected HgCdTe mass,Electron temperatureUnder the assumption of LTE, the electron temperature in the plasma can be determined by relative line intensity two line and . where is the transition probability from energy level m to n, is the statistical weight of the upper energy level, is the energy of the upper energy state m, and T is the electron temperature.,d=1.0 mm,Ti atom,Electron density,The full width of half maximum of the Stark broadening lines is related to the electron density:the first term gives the contribution from electron broadening, and the second is the ion broadening correction; W is the electron impact parameter, A is the ionic-impact broadening parameter, and is the number of particles in the Debye sphere and it is given by: Using the measured broadening data of N II 399.5nm,d=1.0 mm,Pulsed Laser Deposition (PLD),Set up of PLD The Plume Bane of PLD Conclusions,Set Up for PLD,PLD-型脉冲激光溅射沉积设备,Composition of Plume,Contains “atoms, molecules, electrons, ions, clusters, micron-sized solid particulates, and molten globules” Larger particles cause defectsEvaporative materials highly energetic. Increases adatom mobility,Plume Behavioral Characteristics,Extremely dense. Very short collisional mean free paths Rapidly expands. Exhibits hydrodynamical flow. Highly directional. Deposition is suitable to small area.,The Bane of PLD -deposition of micron-sized particulates,Mechanisms Subsurface Boiling Pressure Expulsion Exfoliation Improvement techniques Lower Laser Power Density Mechanical Particle Filter Plume Manipulation Smoothing Target Surface,Subsurface Boiling,Laser superheats subsurface layer before surface reaches evaporation point Surface breaks apart into large (micron-sized) globule particles when the subsurface expands.,Expansion of plume causes sudden drop in pressure just above surface Shock wave pulls droplets of liquid off of surface,Pressure Expulsion,Exfoliation,Thermal shock causes irregularities in surface to break off Surface morphology Previous ablation Particulates are randomly shaped,Conclusions,Disadvantages,Advantages,Almost any material Laser outside chamber. Can vary modes Plume at high energy,Deposition of micron-sized particulates Plume highly directional Uniform only over a small area,SEM pictures showing the surface morphology of (a) 100 , (b) 200 , (c) 300 , (d) 400 , (e) 500 on Si(111) at 200 mJ,SEM observation for ZnO film,Fig.(a) The TEM image of the ZnO thin films deposited at 400 , (b) the electron diffraction pattern for the region.,TEM observation,Comparison of XRD patterns deposition (a) 100 , (b) 200 , (c) 300 , (d) 400 and (e) 500 with 200 mJ/pulse laser incident energy.,XRD observation,XRD of ZnO thin films grown at different laser energies on Si(111),(002),Room temperature PL spectra obtained from the ZnO thin films on Si(111) deposited at different substrate temperatures.,Photoluminescence (PL) spectroscopy,