InGaAs/GaAs quantum dot heterostructures for 3–5 μm IR detectors

Specific features in the formation of InAs quantum dots (QD) by MOCVD were studied in relation to the growing time or equivalent thickness of the InAs layer. TEM and photoluminescence studies have shown that, as the growing time of QDs in a GaAs matrix becomes longer, both the size and shape of the QDs are modified; namely, the aspect ratio increases. Selectively doped multilayer InGaAs/GaAs QD structures were fabricated, and photoconductivity in the IR range was studied for lateral and vertical electron transport. Under a normal incidence of light, intraband photoconductivity in the mid-IR range, 2.5–5 μm, was observed at temperatures of up to 110 K.