The tunable color emission and solid solubility limit in Ba1-xCxAl2O4:Eu-0.001(2+) phosphors was investigated by using cathodoluminescence (CL) and X-ray diffraction (XRD) measurements. The CL spectra showed that the tuning range of the color emission was between 500 and 430 nm. The XRD curves showed that the lattice constant of the (102) plane in the Ba0.6Ca0.4Al2O4:Eu-0.001(2+) phosphor had a minimum value, and that the single phase limit in the Ba1-xCaxAl2O4:Eu-0.001(2+) phosphors is below x value of 0.4. (C) 2000 Elsevier Science Ltd. All rights reserved.