Growth of GaInTlAs alloys on InP has been attempted by solid source molecul
ar beam epitaxy (MBE). Thallium atoms segregate into droplets on the surfac
e at growth temperatures higher than 270 degreesC and evaporate at temperat
ures higher than 350 degreesC. Only in the low temperature range (180-270 d
egreesC) can thallium be incorporated in some conditions, leading generally
to twinned or polycrystalline layers. A narrow window for single-crystalli
ne growth has been found for low Tl contents (4%) using optimized growth co
nditions. (C) 2001 Elsevier Science B.V. All rights reserved.