【摘要】 研究了分子束外延生长的覆盖了1nm的InxAl1 xAs(x=0. 2, 0. 3 )和3nm的In0. 2Ga0. 8As复合应力缓冲层InAs/GaAs自组织量子点(QD)光致发光(PL)特性。加InAlAs层后PL谱红移到1. 33μm,室温下基态和第一激发态间的跃迁能级差增加到86meV。高In组份的InAlAs有利于获得较长波长和较窄的半高宽(FWHM)。对于覆盖复合应力缓冲层的QD不会使波长和FWHM发生显著变化,但可以使基态和第一激发态间的能级差进一步增大。这些结果归因于InAlAs能够有效的抑制In的偏析,减少应力,使QD保持较高的高度。同时,由于InAlAs具有较高的限制势垒,可以增加基态和第一激发态间的能级差。更多还原

【Abstract】 The photon induced fluorecence light （PL） emission characterictics of self-organized quantum dot （QD） at the combined stress buffer layers of In_xAl_1-xAs（x=0.2, 0.3） covering 1nm and In_0.2Ga_0.8As covering 3nm, which were grown at the edge of molecular beam, were studied. When adding InAlAs layer, PL specrum shifts to 1.33μm, the transition energy difference between the groud state and the first excited state increased to 86 meV at room temperature. InAlAs with high percetage of In is in favor of getting a longer wavelength and a narrower line width （FWHM）. For QD covering the combined stress buffer layer it makes no obvious difference to the wavelength and the line width （FWHM）, but will increase the energy difference between the ground and the first excited states. These results are due to that InAlAs can effectively suppress the aisotropicity of In, therefor reducing the stress, and keeping the height of QD relatively high. Because of InAlAs having a relativelyt high restrict potential barrier,the energy difference between the ground and the first excited states can be increased.更多还原