Molecular beam epitaxy and characterization of indium antimonide/aluminum indium antimonide heterostructures

Two-dimensional electron systems were realized in InSb quantum wells with Al0.09In0.91Sb barrier layers delta-doped with Si. Measured electron mobilities in multiple quantum well structures grown on GaAs(001) substrates were as high as 41,000cm2/Vs at room temperature, which is the highest reported value for a semiconductor quantum well, and 380,000cm2/Vs at 6.5K. Simple models can be used to explain the observed dependencies of the electron density on the quantum well to dopant distance and on the number of quantum wells. Dopant compensation was studied for Si delta-doped InSb samples grown on GaAs(001) substrates. Hall effect measurements indicate a sharp decline in electron density with increased substrate temperature, and, along with SIMS measurements, suggest that the temperature dependence of the carrier density results from compensation occurring primarily during growth of the cap layer. Similar behavior was observed in AlxIn1-x Sb samples delta-doped with Si. The recent achievement of high quality quantum wells now allows for optical and low temperature experiments that can be used for the characterization of materials and the study of unique features in the InSb/ AlxIn1-x Sb system.