Optimization of modulation-doped Ga1−xInxAs/InP heterostructures towards extremely high mobilities

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Abstract
This paper presents a study of the electrical and structural properties of inverted modulation‐doped GaInAs/InP heterostructures grown by low‐pressure metalorganic vapor phase epitaxy. First, the thickness of the GaInAs layer was optimized in lattice‐matched samples to find the smallest thickness in which high Hall mobility is observed. Next, in a section closest to the InP the In content was varied. A steady increase of mobility with indium composition was observed. A maximum of 450 000 and 15 500 cm2/V s was obtained for a 10‐nm‐thick Ga1−xInxAs layer with x=0.77 at 6 and 300 K, respectively. Channels with higher indium content exceed the critical thickness and mobility drops off sharply. The decreasing mobility correlates with the formation of misfit dislocations at the interface indicating increasing scattering processes of the GaInAs layer.