EFFECT OF NITROGEN GAS FLOW ON STRUCTURAL, OPTICAL, AND ELECTRICAL PROPERTIES OF N-GAN THIN FILMS GROWN BY HOT WIRE PULSED LASER DEPOSITION

Abstract

GaN thin film was successfully grown on sapphire (0001) substrate using pulsed laser deposition method with hot wire under nitrogen gas atmosphere. To understand the characteristics of the resulting GaN film, observations were made by changing the growth conditions, i.e. temperature up to 750°C and adjusting the nitrogen gas flow rate during the growth process up to 170 sccm. The purpose of these variations is to see how changes in temperature and gas flow affect the quality, structure, and physical properties of the GaN thin films formed. GaN thin films grown at 750°C and supplied with nitrogen gas at a rate of 120 sccm show a wurtzite crystal structure with crystal orientation directions of (0002) and (0004). The wurtzite crystal structure is a common form for GaN and the (0002) and (0004) orientations show its crystal growth direction is parallel to the c-axis of the hexagonal crystal, which usually results in good crystal quality. This material has a bandgap of 3.55 eV, which indicates wide semiconductor properties. In addition, the film exhibits n-type conductivity properties, with a charge carrier density of 1.45 × 10¹⁹ cm-³. The recorded electron mobility is 18.55 cm²/Vs, which reflects the ability of electrons to move within the material when subjected to an electric field.