Electron mobilities in In0.2Ga0.8As/GaAs strained-layer superlattices

Abstract
We report the first Hall effect and resistivity measurements on strained‐layer superlattices (SLS’s) in the (In,Ga)As system. The samples, grown by molecular beam epitaxy, had 60 periods of alternating, 120‐Å‐thick In0.2Ga0.8 As and GaAs layers. Both uniform‐doped and modulation‐doped structures (with Si donors) were studied. Low‐temperature mobilities of over 3×104 cm2/Vs were obtained for structures with doping in only the central 30‐Å region of each GaAs layer. Our results are comparable to reported results on similar (Al,Ga)As superlattices, confirming that high crystalline quality can be obtained in SLS’s with significant mismatch (∼1.4%) and many interfaces (>100).