Tuning the photoluminescence, conduction mechanism and scattering mechanism of ZnSnN₂

The high electron concentration and low mobility of ZnSnN₂ hinder its potential applications in photocatalytic and optoelectronic devices. To reveal the mechanism, herein, ZnSnN₂ thin films were prepared under different sputtering pressure. The results show that impurity band conduction, an electron density of above 10²⁰cm⁻³ and a mobility of 2 cm² V⁻¹ s⁻¹ dominated by variable-range hopping are observed in samples prepared at lower sputtering pressure, due to the unintentional incorporation of substitutional oxygen which is from residual vapour and which substitutes nitrogen, while conduction band conduction, an electron density of 10¹⁹ cm⁻³, a mobility of 24 cm² V⁻¹ s⁻¹ limited by ionized impurity scattering and self-compensation ratio as well as an interband direct recombination emission are found in samples prepared at higher sputtering pressure, due to the decrease in substitutional oxygen doping.