A femtosecond-time-scale photolysis study of vapor-phase GaCl

Abstract

Time-resolved absorption spectra are recorded for Ga atoms produced by the photolytic action of 300 fs, 248.5 nm laser pulses on gas-phase GaCl molecules. Photodissociation of GaCl at 248.5 nm produces both ground-state (2P1/2) and spin–orbit-excited (2P3/2) Ga atoms, resulting in strong transient-absorption features at 403.3 and 417.2 nm, respectively. The experimental spectra are analyzed to obtain the kinetic energy of the photofragments, which is estimated to be ≂0.08 eV for both channels. The analysis suggests that the dissociation limits are (1) Ga 2P1/2+Cl* 2P1/2 for the 403.3 nm channel; and (2) Ga* 2P3/2+Cl 2P3/2 for the 417.2 nm channel. From these results, a new estimate for the dissociation energy of GaCl is obtained: D00=4.80±0.03 eV.

Particle-assisted GaxIn1−xP nanowire growth for designed bandgap structures

“…Methyl groups are known to catalyze HCl dissociation [33] and give rise to methane and free Cl − ions that can react to form chlorides, for example InCl and GaCl [34]. Even though some of the reaction products contribute to NW growth [25] some of the reaction products will desorb and exit the system due to the strong Ga-Cl (4.9 eV [35]) and In-Cl bonds (4.5 eV [36]). The effect of the catalyst particle on In-Cl and Ga-Cl dissociation is beyond the scope of this work, but it would not be surprising to find different reaction rates for the processes.…”

Gas-phase femtosecond transient absorption spectroscopy

“…[27][28][29] Since then, gas-phase femtosecond TAS had gone unnoticed, probably due to its seemingly poor sensitivity. In vapor-phase femtosecond TAS the molecular density is much lower, and therefore a much longer path length must be employed.…”