Arsenic-phosphorus exchange during the formation of InAlAs/InP interfaces

The authors have studied the formation of InAlAs/InP interfaces grown by organometallic-MBE (molecular-beam epitaxy). They analyzed the photoluminescence emission at 5 K of a series of InAlAs/InP samples with different interface growth procedures, taking advantage of recombination across the type II interface which is very sensitive to the interface characteristics. Samples grown with different growth-halts, special interfaces with thin binary layers between the InP and InAlAs layers, and InP samples with an intermediate surface exposure to As/sub 2/ were investigated. TEM (transmission electron microscopy) and ellipsometry measurements are presented. The results are interpreted in terms of a P-As exchange effect during the InAlAs/InP formation. The most stable interface is obtained with the incorporation of a thin AlP interfacial layer, which can be understood by bond strength considerations.<
>