Low temperature stacked electrodes for flexible crystalline semiconductor thin film solar cells

Large area crystalline InP nanomembranes (NM) with p-i-n vertical junction were transferred to flexible plastic substrates, based on low temperature frame assisted membrane transfer process. Low temperature annealing-free stacked electrodes were investigated for the compatibility of energy efficient NM stacking and manufacturing processes. Here we report the properties of stacked contacts between n-InP NMs and different kinds of electrode materials, such as aluminum and indium tin oxide (ITO). The stacked InP NM-ITO contact appears to be excellent ohmic contact, with measured contact resistance of 0.45 ω•cm2. Flexible InP solar cells with stacked back ITO and Al contacts were also fabricated, based on 240 and 1000 nm thick InP NMs. The efficiency of the solar cell with back InP-ITO contact is much higher than the efficient of the cells with back InP-Al contact. Such low temperature energy efficient NM transfer and electrode stacking techniques are highly desirable for a wide range of thin film solar cell manufacturing processes.