ArF Pulsed Laser Research Articles

UV Laser photolysis of C 3O 2 at 193 nm: Emission from electronically excited C, CO and C 2

C 3O 2 was irradiated using an ArF pulsed excimer laser at 193 nm and fluorescence from electronically excited CO and C was observed. The CO(A 1Π → X 1Σ +) fourth positive emission at 200 – 250 nm results from the production of a vibrationally excited CO (X 1Σ +) fragment which is resonantly pumped to the A 1Π( v′ = 1, 4, 7) state at 193 nm. The C(3 1P 0 → 2 1S) emission at 248 nm is attributed to a two-step process; two-photon generation of the C(2 1D) state and consequent resonant excitation of the carbon atom to the 3 1P 0 state. The C 2(d 3Π g → a 3Π u) Swan high pressure band was also observed and was attributed to the collision-induced reaction between C and C 2O.

Nonresonant collision-induced absorption in Xe/Cl2 mixtures

Mixtures of Xe and Cl2 have been irradiated at 193 nm with a pulsed ArF laser. The collision-assisted laser-induced absorption results in emission of XeCl (B and C) at 308 and 340 nm, respectively. The intensity of XeCl emission is found to vary linearly with ArF laser power, indicating the occurrence of a single photon-assisted collision-induced process. The temporal characteristics of the emission vary substantially with the number density of each reagent showing fast formation and decay rates at high densities, but slower rates at lower densities. A kinetic mechanism is proposed in which a (XeCl2) transient complex is initially formed and that complex subsequently dissociates to yield XeCl.

Ohmic contact formation on InP by pulsed laser photochemical doping

Pulsed UV laser photolysis of metal alkyls combined with laser heating has been used to introduce Cd or Zn into p-InP. Ohmic contacts with specific contact resistances of 1.9×10−4 Ω cm2 have been formed using a pulsed ArF laser to photolyze Cd(CH3)2.

Multiphoton-vacuum-ultraviolet laser photodissociation of acetylene: Emission from electronically excited fragments

Acetylene is photolyzed with a high power ArF pulsed excimer laser at 193 nm. Weak CH(A 2Δ→X 2Π) emission at 431.8 nm is shown to result from two-photon absorption by C 2H 2, while strong C 2(A 1Π→ 1Σ g +) Phillips band emission between 690 and 1100 nm likely results from secondary absorption by the C 2H fragment. Weak C 2(d 3Π g→a 3Π u) Swan band emission between 440 and 560 nm originates from a three-photon process. In addition, the C 2(C 1Π g→A 1Π u) Deslandres-d'Azambuja system is identified as weak emission bands in the near UV, overlapping an apparent continuum which extends throughout the visible. Radiative lifetimes of 119 ±6 ns and 10.1 ± 1.2 μs are measured for the C 2d 3Π g(υ′= 0), and A 1Π u(υ′ = 4) states, respectively. The present results indicate that it is possible to generate large yields of high energy fragments with pulsed excimer lasers, opening up an energy region which was only previously accessible with far-vacuum-UV photolysis sources. Such fragments can be spectroscopically characterized, or can be used as reactants in kinetic studies.