UV Laser Photofragment GaCH3 Detected by Far UV Laser Mass Spectrometry

The GaCH z radical has been directly detected by far UV laser mass spectrometry for the first time, as a UV laser photofragment from gaseous trimethylgallium Ga(CHs)3, but not from triethylgallium, Ga(CzHs) 3. The relative yield Y(A) of GaCH 3 was measured, at various UV photolysis laser wavelengths A = 193, 210 and 245 nm, and follows the absorption spectrum of the Ga(CHs) z precursor molecules. PACS: 81.15 Hg, 82.50 Et Even though the GaCH z radical has been considered as one of the main photofragments from UV laser photodissociation of trimethylgallium, no direct evidence has so far been given to identify the existence of this photofragment [1,2]. It is important to detect this radical, not only for finding the mechanism of UV-photodissociation of TMG [1] but also for the understanding of carbon incor0oration in the Laser-MOVPE and ALE (Atomic Laser Epitaxy) using Ga-alkyls as precursor of Ga [3]. In the following experiment, which takes advantage of far UV laser mass spectrometry, we succeeded in a direct detection of the photofragment GaCH 3 from TMG molecules exposed to a UV laser pulse.