Le Système Gazeux Gallium–Chlore: Etude par Spectrométrie Raman. 1–Spectres de Vibration Moléculaire des Espèces Gazeuses: GaCl₃, Ga₂Cl₆, GaCl, Ga₂Cl₄, Ga₂Cl₂ et GaCl₂

Abstract

The molecular vibration frequencies of the gallium–chlorine gaseous species were selected. For the known species Ga2Cl6, GaCl3 and GaCl selection was performed by comparing previous experimental values with our own Raman spectrometric determinations. For the unidentified species Ga2Cl4, Ga2Cl2 and GaCl2 frequency values were evaluated from theoretical literature considerations. The Raman spectra of the vapours obtained by heating condensed gallium and chlorine mixtures are discussed using the selected frequencies and taking into account the Ga2Cl6 and GaCl3 detection limits. With our Raman recording conditions corresponding to well defined spectra, the species are detected up to 5 × 10−3 at. Under these conditions, for Cl/Ga = 3 and between 70 and 500 °C, the main gaseous species are GaCl3 and Ga2Cl6 and the system should be described by the single equilibrium: Ga2Cl6(g)⇌2GaCl3(g). For Cl/Ga = 0.122–3, and between 300 and 800 °C, the representation of the system should be simplified to a single heterogeneous equilibrium between the major species: 2Ga(I)+GaCl3(g)⇌3GaCl(g). In this case, the evolution of the Raman spectra with temperature is explained by taking into account contribution of Ga2Cl4 in very small amounts.

Crystal structure tuning in GaAs nanowires using HCl

“…GaCl and GaCl 3 are assumed to be the major gallium chloride species present. 29 We assume that those general considerations hold as well for our MOVPE process and thus, during growth with HCl, the presence of AsH 3 could limit the etching of the GaAs surface according to eqn (1).…”

Dimeric Molecular Structure of Molten Gallium Trichloride and a Hidden Evolution toward a Possible Liquid–Liquid Transition

“…The melting point of solid GaCl 3 is rather low, 351 K. Surprisingly, little is known on the structure of liquid gallium trichloride; however, the vapor composition and structure of GaCl 3 have been intensively studied using vibrational spectroscopy , and gas electron diffraction. , At low temperature, 322 K, the saturated vapor contains 79% of dimeric Ga 2 Cl 6 and 21% of monomeric GaCl 3 molecules . At high temperature, T > 656 K, the fraction of dimeric molecules is below 2% .…”