The effect of lattice mismatch on hole diffusion lengths in liquid phase epitaxial InGaAsP (λg = 1.15 μm)/InP

Hole diffusion lengths Lp were determined as a function of lattice mismatch for n-type InGaAsP (λg = 1.15 μm) layers grown by liquid phase epitaxy on p+ (100)-InP substrates by measuring the variation of the short-circuit photocurrent as a focused laser beam was scanned along a beveled (∼1°) p-n junction. The longest diffusion length (Lp ∼1.5 μm) was obtained when the epitaxial layer was lattice matched to the InP substrate, and as the mismatch increased either positively or negatively (−0.25%<Δa/a<+0.31%) Lp decreased, indicating that the bulk properties of the layer are influenced by the mismatch at the interface.