In was implanted into bulk ZnO creating a square profile with a thickness of about 100 nm and an In concentration of about 1x10(20) cm(-3). The layer was analyzed with Rutherford backscattering, temperature-dependent Hall effect, and low-temperature photoluminescence measurements. The implantation created a nearly degenerate carrier concentration n of about 2x10(19) cm(-3), but with a very low mobility mu, increasing from about 0.06 cm(2)/V s at 20 K to about 2 cm(2)/V s at 300 K. However, after annealing at 600 degrees C for 30 min, n increased to about 5x10(19) cm(-3), independent of temperature, and mu increased to about 38 cm(2)/V s, almost independent of temperature. Also, before the anneal, no excitons bound to neutral In donors, called I-9 in literature, were observed in the photoluminescence spectrum; however, after the anneal, the I-9 line at 3.3568 eV was by far the dominant feature. Analysis of the Hall-effect data with a parametrized, two-layer model showed that the conduction before the anneal was mainly due to very high concentrations of native donors and acceptors, produced by the implantation, whereas the conduction after the anneal was due to In ions that were nearly 100% activated. These results show that strongly degenerate conductive layers with designed profiles can be created in ZnO with implantation and relatively low-temperature anneals.