摘要
Photoluminescence(PL) from self-organized Ge quantum dots(QDs) with large size and low density has been investigated over a temperature range from 10 to 300 K using continuous-wave(CW) optical excitation.The integrated PL intensity of QDs observed is negligible at about 10 K and rapidly increases with raising temperature up to 100 K.Through analyzing the PL experimental data of the QDs and wetting layer(WL),we provide direct evidence that there exists a potential barrier,arising from the greater compressive strain surrounding large QDs,which could trap carriers in WL at low temperatures and could be overcome via increasing temperature.
Photoluminescence（PL） from self-organized Ge quantum dots（QDs） with large size and low density has been investigated over a temperature range from 10 to 300 K using continuous-wave（CW） optical excitation.The integrated PL intensity of QDs observed is negligible at about 10 K and rapidly increases with raising temperature up to 100 K.Through analyzing the PL experimental data of the QDs and wetting layer（WL）,we provide direct evidence that there exists a potential barrier,arising from the greater compressive strain surrounding large QDs,which could trap carriers in WL at low temperatures and could be overcome via increasing temperature.
基金
supported by the Ministry of Science and Technology of China, the National Natural Science Foundation of China (Grant Nos.10471026 and 10874212)
the National High Technology Research and Development Program of China (Grant No 2006AA03A107)
