Modification of ALE-grown SrS thin films by ion implantation of Cu and codopants

Abstract Atomic Layer Epitaxy (ALE) grown Al 2 O 3 /SrS/Al x Ti y O z /glass films were ion-implanted and annealed to study photoluminescence (PL) characteristics of potential blue color phosphors. 63 Cu + and 37 Cl + or 18 O + ions with partially overlapping spots were implanted with three doses (0.2, 0.6 and 1.7×10 16  at./cm 2 ) using ion energies 60, 80 and 120 keV for 18 O + , 37 Cl + and 63 Cu + , respectively. Cu acts in SrS as an activator, while O and Cl are possible codopants. Samples were annealed in N 2 atmosphere at 600 ∘ C and 800 ∘ C for 2 h. Time-of-flight elastic recoil detection analysis (TOF-ERDA) using 34 MeV 127 I ions as projectiles was utilized to study diffusion of implanted ions and impurity concentrations. All samples showed green PL. Those codoped with 18 O and annealed at 600 ∘ C showed enhanced PL intensity compared to only Cu implanted samples. 37 Cl codoping shifted the peak maximum from 520 nm towards blue by 20 nm without decreasing intensity when annealed at 600 ∘ C. In TOF-ERDA analysis, 18 O was found to diffuse through the SrS/ATO interface, 37 Cl evaporated mainly out and 63 Cu remained inside the SrS film. The oxygen impurity concentration increased when samples were annealed at higher temperatures.