Electrodeposited p-type and n-type ZnSe layers for light emitting devices and multi-layer tandem solar cells

Zinc selenide layers have been grown on glass/conducting glass substrates using a low temperature (similar to 65 degrees C) electrochemical technique, and characterized using X-ray diffractions (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and photo electrochemical cell (PEC) techniques. XRD shows that the material growth is highly preferential with (1 1 1) orientation. XPS work indicates that this material has a chemical and stoichiometric nature similar to that grown by molecular beam epitaxy. Annealing at similar to 250 degrees C for 15 min improves the crystallinity of the layers. PL studies indicate the presence of a low number of defect levels which causes radiative transitions within the energy region 0.7-1.4 eV below the conduction band, in the case of electrodeposited ZnSe when compared to MBE grown ZnSe. Optical properties of the thin films were characterized using a PEC cell arrangement and both n- and p-doping of the materials has been achieved successfully using Ga and As, respectively. The use of crystalline ZnSe layers in both simple p-n junctions and multi-layer solar cell structures shows encouraging results.