Ternary CdxZn1-xSe nanocrystals deposited on Ag(111) by ECALE: AFM and EXAFS characterization

This paper reports the characterization of ternary II–VI semiconductor nanocrystals, deposited by the electrochemical atomic layer epitaxy (ECALE) technique. In particular, morphological and structural properties of the ternary compounds of formula CdxZn1-xSe deposited on Ag (1 1 1) have been characterized as a function of composition. The number of the attainable x values is limited by the necessity of using well-defined ZnSe/CdSe deposition sequences. However, the quantitative analysis carried out on the basis of both electrochemical and extended X-ray absorption fine structure (EXAFS) experiments indicates that the ECALE method is a successfulway of controlling the composition of CdxZn1-xSe. In addition, the electrochemical measurements show that the amount of deposition is minimum in correspondence to the compound with x = 0.5, thus corroborating the hypothesis of a higher degree of disorder suggested both by morphological and structural investigation. The morphology was studied by atomic force microscopy (AFM). The structure of the films is estimated by EXAFS which is a powerful technique for the analysis of the local structure around chosen atoms.