Ternary CdSxSe1-x deposited on Ag(111) by ECALE: synthesis and characterization

Morphology and electronic properties of CdS, CdSe, and the ternary compounds of formula CdSxSe1-x deposited on Ag(111) by ECALE have been characterized as a function of the composition. The number of the attainable x values is limited by the necessity of using well-defined CdS/CdSe deposition sequences. However, the quantitative analysis carried out byXPSand electrochemical stripping experiments indicates that the ECALE method has a good control on composition. The AFM images together with the electrochemical characterization indicate both two-dimensionalandthree-dimensional growth contributions. The photospectra recorded at CdS film electrodes in liquid junction with an alkaline (poly)sulfide electrolyte show good efficiency of photoconversion and band gap typical of the single crystal. Lower photoconversion efficiency and the presence of subband gap response are observed for CdSe; a possible reason is some crystalline disorder due to lower control of the layer-by-layer deposition in the case of Se. The dependence of band gap on composition of ternaryCdSxSe1-xECALEfilms is monotonic and in agreement with literature data reported for bulk materials.