Identification of the acceptor level V3+/2+ in GaAs and a new experimental observation of V2 in “low spin” ground state in GaAs
The results of optical absorption and deel level transient spectroscopy on various V-doped GaAs materials (n type Bridgman, n and p type liquid encapsulated Czochralski,n andp type liquid phase epitaxy) are reported. It is definitively shown that the single acceptor state of isolated vanadium is located atEc-0.14 eV and that no mid gap-level related to isolated vanadium which could explain same reported semi-insulating properties of V-doped GaAs has been detected. From the analysis of the absolute photoionization cross section gs/skno of the above level it is shown that V2+ is in a low spin state in accordance with recent theoretical predictions.