ELECTROABSORPTIVE IN1-XGAXASYP1-Y SUPERLATTICES GROWN BY LIQUID-PHASE EPITAXY

An automatically controlled liquid phase epitaxy process has been developed for the growth of superlattice structures with layers in the thickness range 50-300 nm. Homojunction structures in InP or In1-xGaxAsyP1-y have been grown with from 18 to 102 alternating p and n layers. Heterostructures with undoped layers of smaller band-gap separating the p and n layers have also been produced. A sideways offset of the position of the solutions allowed all p and all n stacks to be deposited at opposite ends of the substrate in addition to the interleaved layers at the centre. Simple ohmic contacts to the p and n ends enabled the electroabsorption characteristics of the central area to be measured for light travelling perpendicular to the junction planes. Only a few volts produced significant changes in absorption at wavelength from 1.2 to 1.3 μm, in agreement with theory.