Atomic layer epitaxy growth of ZnSxSe1-x epitaxial layers lattice-matched to Si substrates

Optical, crystallographic and transport properties of nominally undoped n-type ZnSxSe1-x/Si grown by atomic layer epitaxy have been studied. The lattice of a ZnSxSe1-x. layer with a sulfur content estimated to be about 93% is found to have the best match to the Si substrate, as indicated by XRD, PL and electrical measurements. A narrow X-ray diffraction rocking curve line-width with a minimal FWHM of about 0.16 degrees was observed. PL spectra, obtained at 7 and 300 K, exhibited a strong near band-edge emission and weak deep-level emissions in the longer wavelength region for the ZnS0.93Se0.07 epitaxial layer. Schottky diodes were fabricated from the undoped ZnSxSe1-x layer and the electrical properties were measured at room temperature. From the current-voltage (I-V) characteristics, a high reverse breakdown voltage (> 40 V) and an extremely low cut-in voltage of 0.68 V were obtained with ZnS0.93Se0.07 In addition, a Hall mobility of 347 cm(2)/V s was determined by the Van der Pauw method. These results indicate a good lattice-match of ZnS0.93Se0.07 /Si as a result of low numbers of interface and epitaxial layer defects. (C) 2000 Published by Elsevier Science B.V. All rights reserved.