FORMATION OF HgCdTe (MCT) BY ELECTROCHEMICAL ATOMIC LAYER DEPOSITION: AN INVESTIGATION INTO BANDGAP ENGINEERING

HgCdTe or Mer-Cad-Tel is the most widely used Infrared material. The present study describes the growth of MCT via Electrochemical ALD, using an automated electrochemical flow cell deposition system. Deposits were characterized using X-ray diffraction (XRD), electron probe microanalysis (EPMA) and reflection absorption Fourier transform Infrared spectroscopy (FTIR). As deposited films showed a strong (111) preferred orientation. Changes in deposit composition showed the expected trend in band gaps: the more Hg the lower the band gap, but with some significant deviations. Electrochemical quartz crystal microbalance (EQCM) studies, using an automated flow cell, indicated that some deposited Cd was stripping at potentials used to deposit Hg. In addition, redox replacement of deposited Cd for Hg was evident, a function of the greater stability of Hg than Cd.