Strain distribution in InP/InGaAs superlattice structure determined by high resolution x-ray diffraction

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Abstract
Interfacial strain distribution in a short period InP/InGaAs superlattice structure is evaluated by means of high resolution x‐ray diffraction. The diffraction pattern of the structure allows an unambiguous determination of interfacial strain distribution. From the numerical calculation, positively strained interfacial monolayers at the InP→InGaAs and negatively strained interfacial monolayers at the InGaAs→InP interfaces had to be introduced in order to reproduce the experimental data. At the InP→InGaAs interfaces a group V exchange reaction leading to a positively strained InAs or InAs1−xP interfacial layer is compatible with the simulation. At the InGaAs→InP interfaces negatively strained ternary or quaternary InGaAsyP1−y meet these requirements. The results are consistent with low temperature calorimetric absorption measurements which exhibit a wide band gap InGaAsP‐like absorption feature at 1.48 eV beyond the InP energy gap.