Skip to Main Content
Your organization might have access to this article on the publisher's site. To check, click on this link:http://dx.doi.org/+10.1063/1.4712562
A wurtzite GaAs epilayer grown on a zincblende GaAs substrate by metalorganic chemical vapor deposition is studied by surface photovoltage spectroscopy. The wurtzite structure of the epilayer is disclosed by scanning electron microscope images of surface pits, where the pits are seen to change their structure from a rectangular into a hexagonal shape. The wurtzite phase is also revealed in x-ray diffraction showing a 〈0002〉 diffraction alongside the main (200) diffraction, suggesting a “c” lattice constant of 0.668 nm. A comparison of room temperature surface photovoltage spectra taken from the epilayer sample and from an epilayer-etched substrate suggests a type II heterostructure with valence band difference of about 15 meV and bandgap difference of about 70 meV between the zincblende and the wurtzite GaAs polytypes.