Unveiling the impact of Ta-doping on single crystals β-Ga2O3 (010) grown by optical floating zone method

Abstract

Single crystals of β-Ga₂O₃, oriented along the (010) plane and doped with tantalum (Ta), were grown using the optical-floating zone method. The impact of Ta-doping on the material properties such as structural, electrical, morphological, optical and dielectric behavior of the wafers was examined. The XRD analysis confirmed the (010) orientation, with an observed lattice expansion upon Ta-doping. Raman and HR-TEM analysis support the XRD results. Optical analysis revealed the reduction in bandgap energy on increasing the Ta doping, accompanied by a transmission of ∼80 %. Hall measurements reveals that the free electron concentration increases from 10¹⁷ to 10¹⁸ cm⁻³ as the level of Ta content rises. At lower frequencies, the samples exhibit high dielectric constant followed by a gradual decrease as the frequency increases. The dielectric loss values for all samples remain remarkably low, indicating favorable characteristics for an effective dielectric medium. These results suggest that Ta-doping can be used in β-Ga₂O₃ to enhance the material properties, which can find applications in power electronics and optoelectronic devices.