Epitaxial growth of ZnTe on GaSb(100) using in situ ZnCl2 surface clean

Abstract

The epitaxial growth of high-quality ZnTe on GaSb substrates is demonstrated by molecular beam epitaxy without the use of a group-V beam flux or intermediate GaSb buffer layer. A reduced surface cleaning temperature is achieved using a combination of HCl etching prior to loading into the growth chamber and use of a ZnCl2 flux during the thermal clean step. This procedure results in a surface clean temperature of approximately 440 °C, in comparison to 500 °C for an as-received GaSb substrate, providing a means to achieve a clean GaSb surface for ZnTe epitaxy without the requirement for a group-V flux to stabilize the surface to prevent noncongruent sublimation of GaSb. The resulting ZnTe epitaxial layers demonstrate good surface morphology and structural properties based on Nomarski microscope images, transmission electron microscopy images of the ZnTe/GaSb interface, and x-ray diffraction measurements demonstrating a rocking curve with a full width at half maximum of 40 arc sec for the ZnTe (004) reflection.