InAs quantum dots were formed by depositing monolayers of InAs on GaAs, covered with InGaAs, and hanged with GaAs barriers. This formed a single quantum well in the present study, as grown by molecular-beam epitaxy. Both multiple quantum wells (MQW) and lasers containing such layers were studied. For the MQW structure, the InAs layer thickness affected both the wavelength and intensity of the photoluminescence measured. With increasing InAs thickness, the wavelength changed from about 1.0 to 1.3 mum, with an increasing photoluminescence intensity. The dot size also depended on the InAs layer thickness, ranging from 5 to 20 nm as: analyzed by cross-sectional transmission electron microscopy. The photoluminescence intensity showed different dependence on n- and p-dopnnts, being reduced by the Si doping, but enhanced by the Be-doping. Pulsed lasing at room temperature was observed for the broad area laser fabricated, with a threshold current density of 2 kA cm(-2), at an emission wavelength of 1.06 mum. The effect of growth conditions on the lasing characteristics is also discussed.