  We report Curie temperatures up to 150 K in annealed Ga1-xMnxAs epilayers
grown with a relatively low As:Ga beam equivalent pressure ratio. A variety of
measurements (magnetization, Hall effect, magnetic circular dichroism and Raman
scattering) show that the higher ferromagnetic transition temperature results
from an enhanced free hole density. The data also indicate that, in addition to
the carrier concentration, the sample thickness limits the maximum attainable
Curie temperature in this material - suggesting that the free surface of
Ga1-xMnxAs epilayers is important in determining their physical properties.
