ELECTROCHEMICAL ATOMIC LAYER EPITAXY (ECALE)

Electrodeposition holds promise as a low cost, flexible room temperature technique for the production of II-VI compound semiconductors. Previous studies, however, have resulted in the production of polycrystalline deposits in every case. This paper describes a new method, developed in this laboratory, for depositing these materials epitaxially. The method involves the alternate deposition of the component elements a monolayer at a time. To limit deposition to a monolayer, underpotential deposition (UPD) is employed. UPD occurs because of the enhanced stability provided by bond formation between the II and VI elements, relative to formation of bulk elemental deposits. This method is the electrochemical equivalent of atomic layer epitaxy (ALE), and is thus referred to as "electrochemical atomic layer epitaxy" (ECALE). This paper describes the first example of the ECALE method, involving the thin-layer electrodeposition of CdTe on a Au polycrystalline electrode.