Bulk properties of gallium (Ga)- and aluminum (Al)-doped zinc oxide (ZnO) were studied using bulky single-crystalline thick films grown by liquid phase epitaxy (LPE). The highest possible dopant concentration was 1 x 10(19) cm(-3) for LPE growth at around 800 degrees C. The electron concentration was nearly same to the Ga and AI concentrations. The donor binding energy decreased to nearly zero with an increase in dopant concentration, and electron mobility of the sample with relatively high dopant concentration (1 x 10(19) cm(-3)) was more than 60 cm(2) V-1 s(-1) at room temperature. The LPE technique is a potential solution for the production of ZnO for optical applications because the well-defined excitonic luminescence could be seen from the LPE-grown-doped single-crystals. (C) 2009 Elsevier B.V. All rights reserved.