AFM and XRD investigation of the effect of dissolved oxygen in electrolytes on electrodeposition of CdTe on HgCdTe

Abstract

CdTe films have been deposited onto HgCdTe by potentiostatic electrodeposition at deposition potentials of -0.4 V and -0.5 V with respect to a saturated calomel reference electrode in ethylene glycol base electrolyte. Films deposited with and without nitrogen bubbling to reduce dissolved oxygen in electrolytes were investigated by atomic force microscopy (AFM) and x-ray diffraction (XRD). Significant reduction in roughness (> 1 orders) was observed by bubbling the electrolyte with 6 N nitrogen gas and the resulting films were highly oriented. The reduction in roughness is believed to be the result of the suppression of the reduction reaction whereby the dissolved molecular oxygen is converted to hydrogen peroxide and water that disturbs the ordered CdTe electrodeposition onto HgCdTe wafers.