Microscopic and macroscopic investigation of electrical contacts to n-ZnSe

The formation of Schottky barriers at the Sb/n-ZnSe interface has been investigated for a selected number of chemically etched n-ZnSe surfaces. Microscopic properties of the surfaces and interfaces have been observed with SEM, XPS, AES and SIMS, while the conventional I-V technique has been used to determine the macroscopic electrical properties. Both polycrystalline ZnSe wafers and molecular beam epitaxy-grown layers of n-ZnSe on n(+)-GaAs substrates were used for this investigation. Stoichiometric variations resulting from wet chemical etching of n-ZnSe were investigated using XPS, AES and SIMS techniques. The electrical properties of Sb contacts formed by vacuum evaporation on the etched surfaces were also determined. Possible intermixing at the Sb/n-ZnSe interface was studied using the SIMS imaging technique. The correlation between macroscopic electrical properties and microscopic interactions at the interface will be presented in this paper.