The effect of growth temperature on the optical properties of GaAs/GaNxAs1-
x quantum wells is studied in detail using photoluminescence (PL) spectrosc
opies. An increase in growth temperature up to 580 degrees C is shown to im
prove the optical quality of the structures, while still allowing one to ac
hieve high (> 3%) N incorporation. This conclusion is based on: (i) an obse
rved increase in intensity of the GaNAs-related near-band-edge emission; (i
i) a reduction in band-edge potential fluctuations, deduced from the analys
is of the PL line shape; and (iii) a decrease in concentration of some exte
nded defects detected under resonant excitation of the GaNAs. The thermal q
uenching of the GaNAs-related PL emission, however, is almost independent o
f the growth temperature and is attributed to a thermal activation of an ef
ficient nonradiative recombination channel located in the GaNAs layers. (C)
1999 American Institute of Physics. [S0003-6951(99)03150-2].