Synthesis of the wheat-like CdSe/CdTe thin film heterojunction and their photovoltaic applications

• The wheat-like CdSe array is electrodeposited on ITO substrate.
• Subsequent growth of CdTe by CSS resulted in formation of a continuous film.
• After epitaxial growth of CdTe, the absorption edge shifted from 852 to 915 nm.
• A photocurrent density of 8.34 mA/cm2 has been obtained.

We report on the fabrication of wheat-like CdSe/CdTe thin film heterojunction solar cells made using a simple electrochemical deposition method and close-spaced sublimation technology on indium tin oxide (ITO) substrates. Structural, optical, and electrical properties of the wheat-like CdSe/CdTe thin film junctions were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), energy dispersive spectrometry (EDS), ultraviolet–visible (UV–vis) absorption spectrum and Keithley 2400 analysis. A significant red-shift of the absorption edge is observed in this heterojunction. The heterostructure is composed of the wheat-like CdSe array and CdTe thin film, showing optical properties typical of type II heterostructures that are suited for photovoltaic applications. A photocurrent density of 8.34 mA/cm2 has been obtained under visible light illumination of 100 mW/cm2. This study demonstrates that the electrochemical deposition and the close-spaced sublimation technology, which are easily adapted to other chemical systems, are promising techniques for large-scale fabrication of low-cost heterojunction solar cells.