Pattern formation by changing V/III ratio during growth of GaAs by MOVPE

Rode pointed out that periodically-disturbed surface morphology can occur on epilayers grown on slightly misoriented substrates. Johnson and Legg investigated Rode's prediction in metalorganic vapour phase epitaxy (MOVPE) of AlGaAs at fixed V/III ratio, but no report is available on the faceting as a function of V/III ratio in epilayers of GaAs grown by MOVPE. We have therefore investigated faceting, as function of V/III ratio, during the growth of GaAs by MOVPE at atmospheric pressure, and have found that faceting in epilayers, grown by MOVPE, is not only dependent on misorientation angle but also on the V/III ratio. These layers have characterized by optical microscopy, SEM, photoluminescence (PL), and Hall measurements. Direct correlation between surface morphology and near-band-edge PL has been observed. Mirror-like smooth morphology was obtained at a relatively low V/III ratio (≈15); faceting occur as a ratio is gradually is increased to about 25 and beyond. On the basis of our study, we believe the dimensions of faceting on micrometer scale can be tailored by varying the V/III ratio. These patterns can be utilized in the fabrication of optoelectronic and transferred electron devices, large scale integration of the later being possibl