부산대학교 도서관

The photoreflectance of self-assembled InAs/GaAs quantum dots(QD) grown by MBE were investigated. The results of the InAs/GaAs single layer quantum dots without buffer layer (S1) and with 500 nm buffer layer (S2) are as follows. From the PR measurement as a function of temperature, the PR signal associated with QDs has been observed at low temperature, but it was not observed at high temperature. This was explained by thermal escaping of confined carriers in QDs at high temperature, thus generated electron-hole pair by pump beam cannot modulate the states of QDs. In the case of the QD with buffer layer, PR peaks related with QD and WL are observed at relatively high temperature. This result show that the QD samples with buffer layer has uniform electric field at the surface. Because, the modulation efficiency of PR peaks related QD and WL is increased.