In_xGa_(1-x)As盖层InAs量子点的发光性能研究

Photoluminescence Property of InAs Quantum Dots with In_xGa_(1-x)As Layer Inserted

用分子束外延系统在GaAs(001)衬底上生长InAs量子点,在InAs量子点上插入3 nm的In0.4Ga0.6As层,可将量子点发射波长调谐到1 300 nm附近.对样品进行氢等离子处理,研究处理前后样品的InAs量子点光致发光(PL)强度的变化.结果表明,在InAs量子点与相邻层的界面上以及GaAs层中存在界面缺陷,采用氢等离子处理可有效地抑制界面缺陷,大幅度地提高发光效率.

InAs quantum dots （QDs） have been grown on the GaAs （001） substrates by the method of molecular beam epitaxy. The emission of InAs QDs can be turned to about 1 300 nm by the introduction of a 10ML In0.4Ga0.6As layer. The photoluminescence of the samples were studied before and after being treated by hydrogen plasma. The results show that the enhancement of the PL intensity after H-plasma treatment depends on the excitation power, from about a factor of 12 at the low excitation limit to about a factor of 2 at the highest excitation power used in this study, which are probably due to competition between carrier capture by nonradiative centers and InAs QDs. PL intensity variation with the chauge of time and temperature were also investigated, and the results of them clearly illustrate that there indeed exist interface defects, both on the interface between the InAs dots and surrounding layers and in the GaAs layers, which can be suppressed heavily by H-treatments so that the PL intensity can be enhanced greatly.