The surface leakage currents of CdZnTe wafers

The surface leakage currents (SLCs) and surface sheet resistances (SSRs) of CdZnTe (1 1 0), (1 1 1) A and (1 1 1) B surfaces after etching with Br-MeOH solution, chemo-mechanical polishing (CMP) and passivation were measured in the parallel stripe model, respectively. Meanwhile the surface compositions were determined by X-ray photoelectron spectroscopy (XPS). Te enrichment introduced by etching with Br-MeOH resulted in the increase of the SLCs of CdZnTe wafers. After chemo-mechanical polishing, Te enrichment was removed, and SLCs decreased. CdZnTe (1 1 1) B without Te enrichment possesses higher SLC than that of (1 1 1) A, and (1 1 0) surface has the lowest SLC, which should be attributed to the lower surface dangling bonds. Passivation treatment with NH4F + H2O2 is an effective method to decrease SLCs of CdZnTe, by which the SLC was decreased two orders.