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

Atomic Layer Epitaxy (ALE) grown Al2O3/SrS/AlxTiyOz/glass films were ion-im planted and annealed to study photoluminescence (PL) characteristics of pot ential blue color phosphors, Cu-63(+) and Cl-37(+) or O-18(+) ions with par tially overlapping spots were implanted with three doses (0.2, 0.6 and 1.7x 10(16) at./cm(2)) using ion energies 60, 80 and 120 keV for O-18(+), Cl-37( +) and Cu-63(+), respectively. Cu acts in SrS as an activator, while O and Cl are possible codopants, Samples were annealed in N-2 atmosphere at 600 d egrees C and 800 degrees C for 2 h, Time-of-flight elastic recoil detection analysis (TOF-ERDA) using 34 MeV I-127 ions as projectiles was utilized to study diffusion of implanted ions and impurity concentrations. All samples showed green PL. Those codoped with O-18 and annealed at 600 degrees C sho wed enhanced PL intensity compared to only Cu implanted samples. Cl-37 codo ping shifted the peak maximum from 520 nm towards blue by 20 nm without dec reasing intensity when annealed at 600 degrees C. In TOF-ERDA analysis, O-1 8 was found to diffuse through the SrS/ATO interface, Cl-37 evaporated main ly out and Cu-63 remained inside the SrS film. The oxygen impurity concentr ation increased when samples were annealed at higher temperatures. (C) 1999 Elsevier Science B.V. All rights reserved.