Title: Tailoring Heterovalent Interface Formation with Light,
Abstract: Integrating different semiconductor materials into an epitaxial device
structure offers additional degrees of freedom to select for optimal material
properties in each layer. However, interface between materials with different
valences (i.e. III-V, II-VI and IV semiconductors) can be difficult to form
with high quality. Using ZnSe/GaAs as a model system, we explore the use of UV
illumination during heterovalent interface growth by molecular beam epitaxy as
a way to modify the interface properties. We find that UV illumination alters
the mixture of chemical bonds at the interface, permitting the formation of
Ga-Se bonds that help to passivate the underlying GaAs layer. Illumination also
helps to reduce defects in the ZnSe epilayer. These results suggest that
moderate UV illumination during growth may be used as a way to improve the
optical properties of both the GaAs and ZnSe layers on either side of the
interface.