Electroless deposition of Au, Pt, or Ru metallic layers on CdZnTe

The electrical and structural properties of thin metallic layers (Au, Pt, or Ru) on CdZnTe (CZT) deposited by electroless deposition method have been investigated by means of atomic force microscopy (AFM), scanning electron microscopy (SEM), and Rutherford backscattering spectroscopy (RBS) measurements. SEM and AFM techniques put in evidence the modification of the morphology and the contact's roughness dependence with the deposition time. The surface of the Pt or Ru layer on a CZT material presents micro-cracks at a critical thickness, whereas it does not occur with the Au layer. The thickness of the Au layer with different deposition times obtained by RBS indicates first a fast increase in thickness for short deposition times and then saturation to an asymptotic value of 120 nm after 1 h.

► Modification of morphology and roughness depending on the time of deposition.
► Appearance of cracks for Pt and Ru layers after a certain critical thickness.
► Rapid initial increase in thickness for the Au layer and then saturation at 120 nm.
► Due to the layers' porosity, the thickness of TeO2 increases with deposition time.
► Pt is a polycrystalline layer but Ru is deposited epitaxially on CdZnTe.