We demonstrate that GaMnAs films grown with As2 have excellent structural,
electrical and magnetic properties, comparable or better than similar films
grown with As4. Using As2, a Curie temperature of 112K has been achieved, which
is slightly higher than the best reported to date. More significantly, films
showing metallic conduction have been obtained over a much wider range of Mn
concentrations (from 1.5% to 8%) than has been reported for films grown with
As4. The improved properties of the films grown with As2 are related to the
lower concentration of antisite defects at the low growth temperatures
employed.Comment: 8 pages, accepted for publication in J. Crystal Growt