Pulsed Laser Deposition with in situ Diagnostics

Time-resolved ICCD-imaging and spectroscopy of laser vaporization processes and pulsed laser deposition (PLD) is performed to understand the laser vaporization processes responsible for the synthesis of thin films, nanoparticles, and 2D materials on substrates, or in the gas phase. 

Science Overview

This fully-functional PLD chamber is equipped with target carousel and substrate heater, but also a full set of diagnostic capabilities to record the laser plasma evolution leading to the synthesis of thin films or 2D crystals on substrates, or nanoparticles that are formed in the gas phase. These diagnostics are important to understand the kinetic energy of the plume species that are generated by laser ablation of the target by the excimer laser (Coherent LPX Pro, 25 ns pulsed KrF (248 nm) ultraviolet laser, 1 J/pulse, variable repetition rate) and reactions with background gases that are used during deposition. A number of spectroscopic diagnostic techniques are used, some of which include the introduction of a second laser beam sheet (Continuum Sunlite and OPO providing 10 ns pulses of tunable light from 250 nm to 1500 nm) that is used as a probe of the ablated material at a time delay after the ablation laser pulse.

Applications

The in situ diagnostics PLD chamber is used to explore the deposition of novel new experimental nanomaterials and nanoparticles, such as hierarchical nanoparticle films [1], and atomically-thin two-dimensional semiconductor materials [2-4].

Specifications

• Laser Ablation Chamber: Turbopumped to 5e-07 Torr, control valves for constant pressure gas introduction, resistive heater to 850°C for pulsed laser deposition, with dual 8” Suprasil side windows allow imaging/spectroscopy, multi-target carousel for automated switching of 4 horizontally-mounted targets, ion probe, top/bottom windows for introduction of second, time-delayed laser for spectroscopy as sheet beam
• Excimer laser: Coherent LPX Pro, 25 ns pulsed KrF (248 nm), 1 J/pulse
• Probe laser: Continuum Sunlite Nd:YAG laser and Optical Parametric Oscillator system providing 10 ns pulses of tunable light from 250 nm to 1500 nm
• Gated-intensified CCD imaging system: Princeton Instruments, tunable >5ns gate, UV-Nikkor lens, timing controlled with SRS DG535 digital delay generator
• Spectroscopy system: Acton 0.3m spectrometer with 150g/mm, 300g/mm, and 1200g/mm gratings, with computer-controlled, gated, intensified Princeton Instruments Pixis detector.