【摘 要】
：
GaAs/Ge heterostructures have been employed in various semiconductor devices such as solar cells,high-performance CMOS transistors,and Ⅲ Ⅴ/Ⅳ heterogeneous op
【机 构】
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Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sci
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GaAs/Ge heterostructures have been employed in various semiconductor devices such as solar cells,high-performance CMOS transistors,and Ⅲ Ⅴ/Ⅳ heterogeneous optoelectronic devices.The performance of these devices is directly dependent on the material quality of the GaAs/Ge heterostructure,while the material quality of the epitaxial GaAs layer on the Ge is limited by issues such as the antiphase domain (APD),and stacking-fault pyramids(SFP).We investigate the epitaxial growth of high-quality GaAs on a Ge (001) mesa array,via molecular beam epitaxy.Following a systematic study of the Ge terrace via an in situ scanning tunneling microscope,an atomi-cally step-free terrace on the Ge mesa measuring up to 5 × 5 μm2 is obtained,under optimized growth conditions.The step-free terrace has a single-phase c (4 × 2) surface reconstruction.The deposition of a high-quality GaAs layer with no APD and SFP is then achieved on this step-free Ge terrace.High-resolution transmission electron microscopy and electron channel contrast image characterizations reveal the defect-free growth of the GaAs layer on the step-free Ge mesa.Furthermore,InAs quantum dots on this GaAs/Ge mesa reveal photoluminescent intensity comparable to that achieved on a GaAs substrate,which further confirms the high quality of the GaAs layer on Ge.
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