Study on the effect of different InAs growth rates on the photoluminescence properties of InAs/GaAs submonolayer quantum dots

Abstract A series of InAs/GaAs submonolayer quantum dot (SML-QD) structures was fabricated using molecular beam epitaxy (MBE). These structures were systematically characterized using atomic force microscopy (AFM), high-resolution x-ray diffraction (HRXRD), and photoluminescence (PL) spectroscopy. This study examined the effect of the InAs growth rate on the surface morphology, structural strain, and photoluminescence properties of SML-QDs. Results indicate that adjusting the growth rate effectively modulates the surface morphology and optical properties of InAs/GaAs SML-QDs. At a growth rate of 0.03 Ml s −1 , AFM images revealed a step-flow growth mode. HRXRD analysis indicated minimal strain and no evidence of relaxation, suggesting optimal crystal quality under this condition. Temperature-dependent PL measurements confirmed that the optical bandgap of this sample obeyed the Varshni equation, demonstrating excellent thermal stability. Furthermore, fitting the temperature-dependent PL data with the Arrhenius equation yielded the highest carrier activation energy for this sample, indicating its exceptional capability to suppress thermal carrier escape and non-radiative recombination. In summary, optimizing the growth rate enables the controlled preparation of high-performance InAs/GaAs SML-QDs, demonstrating significant application potential in optoelectronic devices.