Synthesis of High-Quality Multilayer Hexagonal Boron Nitride Films on Au Foils for Ultrahigh Rejection Ratio Solar-Blind Photodetection.

Solar-blind photodetectors have widespread applications due to the unique merit of "black background" on the earth. However, most solar-blind photodetectors reported previously underwent quite low rejection ratio (R200 nm/R280 nm < 103), and were interfered by the light longer than 280 nm. Herein, by an ambient pressure chemical vapor deposition (CVD) method, large-area, clean and uniform two-dimensional (2D) multilayer h-BN films with different thickness have been successfully synthesized on Au foils. The synthesized multilayer h-BN film is transparent to spectra longer than 280 nm, showing excellent optical and optoelectronic properties to weak solar-blind light (μW/cm2). This sensitive solar-blind h-BN photodetector exhibits ultrahigh rejection ratio (R220 nm/R280 nm >103 and R220 nm/R290 nm>104), low dark current (102 fA), large detectivity (3.9 × 1010 Jones). It is noteworthy that the rejection ratio (R220 nm/R290 nm) here is superior to most previous ones based on traditional semiconductors. This large-scale, clean and uniform multilayer h-BN film will contribute to the progress of next generation optoelectronic devices.