Direct growth of hexagonal boron nitride films on dielectric sapphire substrates by pulsed laser deposition for optoelectronic applications
Gaokai Wang, Jingren Chen, Junhua Meng, Zhigang Yin, Ji Jiang, Yan Tian, Jingzhen Li, Jinliang Wu, Peng Jin, Xingwang Zhang
Abstract
Recently, hexagonal boron nitride (h-BN), an ultra-wide bandgap semiconductor, has attracted considerable attention owing to its excellent properties. In thin films grown on metal catalysts, contamination and damage induced by a transfer process cannot be avoided. Therefore, synthesizing h-BN films on non-catalytic dielectric substrates is desirable for electronic applications. In this study, we demonstrate the direct growth of high-quality h-BN films with a controllable thickness on sapphire substrates by using the pulsed laser deposition (PLD) technique. The effects of the deposition conditions and laser parameters on the growth of the h-BN films are systematically investigated by evaluating their characteristic Raman peaks. Among the various growth parameters studied, the substrate temperature has the greatest influence on the crystalline quality of the h-BN films, and the optimal pressure varies depending on the target-substrate distance. The h-BN film grown under optimal conditions exhibits a narrow Raman line width of ∼30 cm−1, indicating a high crystalline quality. The photodetectors fabricated from the PLD-grown h-BN films exhibit superior deep-ultraviolet detection performance with a large on/off ratio of >104, high photoresponsivity, and a sharp cut-off wavelength of 220 nm. This study presents the possibility of producing high-quality h-BN films by applying PLD on dielectric substrates for optoelectronic applications.