Investigation of Sputtered Oxides and p+ Back-contact for Polycrystalline CdTe and CdSeTe Photovoltaics

Adding a thin layer of Al2O3 to the back of CdSeTe/CdTe devices has previously been shown to passivate the back interface and drastically improve surface recombination lifetimes. Using such a structure, lifetimes of over 400 ns have been recorded. Despite this, such devices do not currently show an improvement in open-circuit voltage (VOC) that is commensurate with this effect. Devices were fabricated using a range of Al2O3 thicknesses at the back interface. High efficiency devices exceeding 16.4% were fabricated with 0.5 nm Al2O3.