Comparison of structural and optical properties of GaSb/AlGaSb quantum well structures grown on different oriented Si substrates

Abstract: We report on the molecular beam epitaxy (MBE) of GaSb films and GaSb/AlGaSb multiple quantum well (MQW) structures grown on Si(111) and Si(011) substrates using an AlSb initiation layer. The structural and optical properties of the films on the different oriented Si substrates were characterized by cross-sectional transmission electron microscopy (TEM), high-resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), and photoluminescence (PL) measurements. The GaSb films and the MQW structures grown on Si(011) were found to have rather rough surfaces and of poor crystallinity under the present growth condition with the AlSb initiation layer. In contrast, the films grown on Si(111) indicated a mirror surface, definite MQW structures, and HRXRD patterns. The PL emissions within the 1.3–1.5μm for the MQW structures on Si(111) and Si(011) were observed at the temperatures up to 300 and 200K, respectively. We found that the PL peak energy, around 1.5μm, of the MQW structures grown on Si(111) is almost temperature independent up to ∼120K and exhibits a smaller variation with increasing temperature compared to those of the samples grown on Si (001) substrates. In the case of the MQW on Si (011), the PL peak energy as a function of temperature showed an intermediate behavior between those grown on Si(111) and Si(001) substrates. [Copyright &y& Elsevier]