Growth and characterization of Cd1-xZnxTe (0 \leq x \leq 1) nanolayers grown by isothermal closed space atomic layer deposition on GaSb and GaAs

Abstract

In this work are presented the results obtained from the deposition of Cd1-xZnxTe nanolayers using as precursor the vapours of the elements Zn, Te, and a mixture of Cd and Zn on GaAs and GaSb (001) substrates by Atomic Layer Deposition technique (ALD), which allows the deposition of layers of nanometric dimensions. At each exposure of the growth surface to the of cation or anion precursors vapours, this surface is saturated. Therefore, it is considered that the process is self-regulated. The ZnTe layers were grown in a wide range of temperatures; however, ZnTe nanolayers with a shiny mirror-like surface could be grown at temperatures between 370 and 410oC. Temperatures higher than 400oC were necessary for the CdTe growth. The layers of the Cd1-xZnxTe ternary alloy were deposited at temperature range of 400 and 425oC. The grown nanofilms were characterized by Raman spectroscopy and high-resolution X-ray diffraction. The Raman spectrum shows the peak corresponding to LO-ZnTe at 208 cm-1, which is weak and is slightly redshifted in comparison with the reported for the bulk ZnTe. For the case of the CdTe nanolayers, Raman spectrum presents the LO-CdTe peak, which is indicative of the successfully growth of the nanolayers, its weakness and its slight redshifted in comparison with the reported for the bulk CdTe can be related with the nanometric characteristic of this layer. The performed high resolution X-ray diffraction measurements allowed to study some important characteristics, as the crystallinity of the grown layers. Additionally, the performed HR-XRD measurements suggest that the crystalline quality have dependence with the growth temperature.