Composition control of pulsed laser deposited copper (I) chalcogenide thin films via plasma/Ar interactions

Abstract

We present how the applied Ar background pressure correlates to the cation and anion composition of Cu(I) chalcogenide thin films grown by pulsed laser deposition (PLD). The as-grown films produced at ∼10−2 mbar pAr show a more pronounced deficiency in lighter composition, as compared with using quasi-vacuum or ∼10−1 mbar. The thermoelectric performance of the as-grown Cu2Se varies consistently with the respective changes in Cu/Se ratio vs. pAr. The optimum thermoelectric performance of Cu2Se is achieved by growing in vacuum or quasi-vacuum, where dense and even thin film morphology is obtained while the cation/anion composition is more congruent than at higher pAr.