Tunable band offsets via control of interface atomic configuration in GaAs-on-ZnSe(001) heterovalent heterostructures

The tunability of band offsets in GaAs/ZnSe(001) heterovalent heterostructures is investigated. The surface of GaAs grown on ZnSe by metalorganic vapor phase epitaxy is atomically flat under the condition employed in this study, which is indicative of the formation of the abrupt interface. Between the growth of ZnSe and GaAs, interval is introduced for purging a Se source precursor. After the interval, the GaAs growth begins with an initial exposure of ZnSe to an As precursor. The durations of the interval and the As exposure are the parameters to control the interface chemistry. During the interval, atoms on the ZnSe surface change from Se to Zn. As the duration of the As exposure lengthens, on the other hand, either Zn or Se atoms appear alternately on the ZnSe surface, because the As precursor etches ZnSe digitally. Using these characteristics, the valence band offsets in GaAs/ZnSe(001) heterostructures are controlled between 0.6 and 1.1 eV. (C) 1999 American Institute of Physics. [S0021-8979(99)05803-X].