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The pristine and diethylenetriamine (DETA)-doped tungsten disulfide quantum dots (WS2 QDs) with an average lateral size of about 5 nm have been synthesized using pulsed laser ablation (PLA). Introduction of the synthesized WS2 QDs on the InGaAs/AlGaAs quantum wells (QWs) can improve the photoluminescence (PL) of the InGaAs/AlGaAs QW as high as 6 fold. On the basis of the time-resolved PL and Kelvin probe measurements, the PL enhancement is attributed to the carrier transfer from the pristine or DETA-doped WS2 QDs to the InGaAs/AlGaAs QW. A heterostructure band diagram is proposed for explaining the carrier transfer, which increases the hole densities in the QW and enhances its PL intensity. This study is expected to be beneficial for the development of the InGaAs-based optoelectronic devices.

Si δ-doped AlGaAs/InGaAs/AlGaAs quantum well (QW) structure is commonly adopted as one of the core elements in modern electric and optoelectronic devices. Here, the time dependent photoconductivity spectra along the active InGaAs QW channel in a dual and symmetric Si δ-doped AlGaAs/InGaAs/AlGaAs QW structure are systematically studied under various temperatures (T = 80–300 K) and various incident photon energies (E in = 1.10–1.88 eV) and intensities. In addition to positive photoconductivity, negative photoconductivity (NPC) was observed and attributed to two origins. For T = 180–240 K with E in = 1.51–1.61 eV, the trapping of the photo-excited electrons by the interface states located inside the conduction band of InGaAs QW layer is one of the origins for NPC curves. For T = 80–120 K with E in = 1.10–1.63 eV, the photoexcitation of the excess ‘supersaturated’ electrons within the active InGaAs QW caused by the short cooling process is another origin.