Fig. 4. θ − 2θ X-ray diffraction patterns of (100 − x)ZnO–xB2O3 ceramic targets with
various contents of B2O3. The ZnO–B2O3 ceramic target preserves the hexagonal ZnO
structure (JCPDS 65-3411) for all the samples. As the content of B2O3 increases, a
monoclinic Zn3B2O6 phase (JCPDS 37-1486) becomes obvious in the diffraction patterns.