• Journal of the Korean Vacuum Society
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• v.20 no.6
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• pp.449-455
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• 2011

The luminescence properties of $In_{0.5}Ga_{0.5}As/In_{0.5}Al_{0.5}As$ multiple quantum wells (MQWs) grown on $In_{0.4}Al_{0.6}As$ buffer layer have been investigated by using photoluminescence (PL) and time-resolved PL measurements. A 1-${\mu}m$-thick $In_{0.4}Al_{0.6}As$ buffer layers were deposited at various temperatures from $320^{\circ}C$ to $580^{\circ}C$ on a 500-nm-thick GaAs layer, and then 1-${\mu}m$-thick $In_{0.5}Al_{0.5}As$ layers were deposited at $480^{\circ}C$, followed by the deposition of the InGaAs/InAlAs MQWs. In order to study the effects of $In_{0.4}Al_{0.6}As$ layer on the optical properties of the MQWs, four different temperature sequences are used for the growth of $In_{0.4}Al_{0.6}As$ buffer layer. The MQWs consist of three $In_{0.5}Al_{0.5}As$ wells with different well thicknesses (2.5-nm, 4.0-nm, and 6.0-nm-thick) and 10-nm-thick $In_{0.5}Al_{0.5}As$ barriers. The PL peaks from 4-nm QW and 6-nm QW were observed. However, for the MQWs on the $In_{0.4}Al_{0.6}As$ layer grown by using the largest growth temperature variation (320-$580^{\circ}C$), the PL spectrum only showed a PL peak from 6-nm QW. The carrier decay times in the 4-nm QW and 6-nm QW were measured from the emission wavelength dependence of PL decay. These results indicated that the growth temperatures of $In_{0.4}Al_{0.6}As$ layer affect the optical properties of the MQWs.