Anomalies in the Temperature Dependence of the Photoelectrical Response of GaAs/InGaP Superlattices

Photoelectrical measurements were taken on InGaP (p(+))-GaAs/InGaP-InGaP (n(+)) multilayers structures, formed by a sequence of nominally undoped InGaP/GaAs quantum wells, interposed between two p(+) and n(+) InGaP cladding layers. The heterostructures were grown through Low Pressure Metal Organic Vapour Phase Epitaxy, with liquid precursors for the III-V elements and growth conditions optimized for obtaining sharp interfaces and negligible ordering effects in InGaP. The experimental temperature dependence of the photoelectrical signal intensity exhibited peculiarities and anomalies which could lead to erroneous analysis of the perpendicular transport mechanisms, so that they are here critically discussed in the light of a partial depletion of the nominally intrinsic superlattice region of the p-i-n structure.