Growth by molecular-beam epitaxy and characterization of (InAs)m(GaAs)m short period superlattices on InP substrates

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Abstract
(InAs)m(GaAs)m short period superlattices (SPSs) have been grown by molecular‐beam epitaxy on InP substrates with their layer index m value systematically changed from 1 to 3. Their structural and electrical property dependencies on the layer index m value have been examined. During the first growth stage for the SPSs, with layer index m values of 2 and 3, two‐dimensional reflection high‐electron energy diffraction growth patterns were observed. The intended periodic structures without misfit dislocation generation were confirmed by x‐ray diffraction and transmission electron microscopy (TEM) measurements. However, the obtained electrical properties were still poor, indicating the existence of a large amount of disorder in the SPSs. On the other hand, though the thickness of consisting binary compounds was as thin as one monolayer, a high‐quality (InAs)1(GaAs)1 SPS was obtained. The highly ordered monolayer arrangement for InAs and GaAs was first observed by a TEM lattice image as well as x‐ray diffraction measurement. The obtained electron Hall mobilities for the modulation‐doped N‐AlInAs/(InAs)1(GaAs)1 SPS structure were as high as 11 000 cm2/V s at room temperature and 74 000 cm2/V s at 25 K.