Epitaxy of Hexagonal Boron Nitride Thin Films on Sapphire for Optoelectronics
Gaokai Wang, Junhua Meng, Jingren Chen, Yong Cheng, Jidong Huang, Siyu Zhang, Zhigang Yin, Ji Jiang, Jinliang Wu, Xingwang Zhang
Abstract
Recently, wide band gap hexagonal boron nitride (h-BN) has drawn considerable attention because of its superior properties and potential for optoelectronics applications. However, extremely high substrate temperatures are usually required to obtain highly crystalline h-BN films on dielectric substrates, which is highly desired for most electronic device applications. In this work, wafer-scale high-crystalline-quality h-BN films have been obtained via high-temperature annealing on PLD-grown amorphous BN films. It is found that the annealed h-BN film is epitaxially grown on sapphire with an orientation relationship: h-BN (0001)[11̅00]//sapphire (0001)[11̅00]. The narrow Raman peak and XRD rocking curve, as well as the observed strong excitonic emission, indicate the high crystalline quality of our epitaxial h-BN films. Moreover, the photodetectors fabricated from the annealed h-BN films exhibit an excellent device performance, suggesting that high-temperature annealing is a simple and promising strategy to obtain highly crystalline h-BN films for optoelectronic device applications.