Journal of Ovonic Research Vol. 18, No. 6, November - December 2022, p. 797 - 804 A first-principles investigation into the electronic characteristics of phase changes in ZnO at high pressures Y. Benkrima a* , M.E. Soudani b , D. Belfennache c , H. Bouguettaia d , A. Souigat a a Department of Exact Sciences, ENS Ouargla, Algeria. b Laboratory of New and Renewable Energy in Arid and Saharan Zones (LENREZA),Faculty of Mathematics and Matter Sciences, Kasdi Merbah University 30000 Ouargla, Algeria. c Research Center in Industrial Technologies CRTI, P.O. Box 64, Cheraga, 16014 Algiers, Algeria. d Department of Physics, Faculty of Mathematics and Matter Sciences, Kasdi Merbah University, P.O. Box 511, 30000 Ouargla, Algeria. The current study focuses on the effect of pressure on zinc oxide, ZnO, which is considered an essential element in several fields. In this research, the method of calculation has been used from the commencement to find the ZnO compound's structural and electrical characteristics at various pressure levels. It is found that the obtained results related to the crystal structure of the compound with phase (B4) Wurtzite agree well with previous theoretical and experimental findings. In addition, the electronic properties showed that ZnO has a direct gap of 0.68 eV, and the density of states showed that the3d position of the zinc atom significantly contributed to building the density of the electronic states of the compound, followed by the P-terminal of the oxygen atom. As it became clear to us that changing the pressure applied to the oxide ZnO increases the value of its energy gap, while the pressure value of 13.38 GPa is the crystal transition point from phase (B4) to (B1). (Received October 4, 2022; Accepted December 6, 2022) Keywords: Density function theory (DFT), ZnO, Phases, Pressure, Electronic properties. 1. Introduction Zinc oxide, ZnO is one of the most important semiconductor, with a broad direct and estimated energy gap of 3.4 eV, with very large exciton energy estimated at60 mega volts [1-4]. Recently, scientists have concentrated on a large number of semiconductors, due to their multiple advantages at the industrial and technological level [5-7]. Indeed, ZnO has remarkable and diverse applications, including gas sensors, photo catalysts and thin layers related to electronic and electro-optical devices [8-12].Under normal conditions, the dynamically stable phase of ZnO is the four surface wurtzite (B4) phase with covalently bonded Sp3[13]. Moreover, ZnO high- pressure behavior is of tremendous and unique interest, whereby many theoretical studies have been conducted in this field as presented in the works [14,15]. In this respect, experimental studies also showed that the stable phase wurtzite could change its phase to rock salt (B1) phase at about 10 GPa16.Likewise, the results of the experimental study carried out by John C. Jamieson [17] showed the transformation that occurs in semi-conductor compounds when pressurized within the temperature range of 300K.It has been emphasized by many researchers theta type II-VI semiconductor subjected to a high pressure, so to speak, (8±3) GPa, at room temperature, transforms its (B4) phase to (B1) phase. It has been proven that the Pseudo-Potential (PP) method is one of the most widely used for calculating electronic structures. In this respect, the present work tackles the effect of pressure on the compound ZnO (wurtzite) and on the energy gap. This was achieved by utilizing the Density Function Theory (DFT) and the Siesta program. * Corresponding author: benkrimayamina1@gmail.com https://doi.org/10.15251/JOR.2022.186.797