Abstract. In this study, we reported the effect of applied compaction pressure on green body and electric current heating on ceramic bar on the ZnO crystal growth and its photoluminescence characteristic. Crystals grown on ZnO bar sintered by 1100 o C were mostly on (1 0 1) orientation. Sample with 3.0 ton and 3.0 A for applied pressure and current, respectively revealed the shortest photoluminescence (PL) wavelength of 409.5 nm with highest emission energy of 3.03 eV. IntroductionZnO has gained substantial interest in the research community because of its large exciton binding energy (60 meV) and wide direct band gap (Eg ∼ 3.37 eV) at room temperature (R.T.). This large exciton binding energy paves the way for an intense near-band-edge excitonic emission such as lasing action at R.T. and higher temperatures, because this value is 2.4 times larger than that of the room temperature thermal energy (kBT = 25 meV). In addition, the interest in ZnO is fueled and fanned by its prospects in electronics and photonics applications, viz. transparent electrodes in solar cells, flat display devices and novel solid-state ultraviolet (UV) lasers owing to its direct wide band gap [1][2][3][4][5][6][7].Many works have been done on the fabrication of ZnO micro/nanostructures with high aspect ratios using metalorganic chemical vapor deposition [8], thermal evaporation and thermal decomposition [9]. But these techniques appear to be involved process with many complex steps, require sophisticated equipment and rigorous experimental conditions. However, some of them have drawbacks like long reaction time, toxic templets and exotic metal catalysts, and low purity or poor crystallite quality of products, which may influence the quality and applications of ZnO. So there is still the need for developing a method that can produce the ZnO micro/nanostructures in laboratory environment with high quality, high repeatability and low cost process for a wide range of applications. Hence, a novel technique called ECH for the preparation of ZnO micro/nanocrystals [10][11][12].When a certain direct current flowed through a sample of ZnO ceramic bar, the sample was Jouleheated, and the crystal growth occurred. ZnO is a key technological material. The lack of a centre of symmetry in wurtzite, combined with large electromechanical coupling, results in strong piezoelectric