Multilayer'-4H-borophene growth on gallium arsenide towards high-performance near-infrared photodetector.

Multilayer borophene was predicted to have a similar semiconductor property to its monolayer arise from the weak van der Waals interactions between the layers. Besides, multilayer borophene has a higher carrier mobility than monolayer ones, so it is placed great hopes in applications of photoelectric and photovoltaic devices. However, its preparation and application in experiments of multilayer borophene are still lacking. Here, multilayer'-4H-borophene was synthesized on semiconducting-type GaAs substrates using NaBHsource as precursor and hydrogen as the carrier gas under controlled temperature and pressure conditions. The experimental results of the borophene are in good agreement with those of its theoretical prediction. The borophene is a semiconductor with a bandgap of 2.48 eV. To demonstrate the device application potential of the borophene, a near-infrared photodetector composed of-type borophene and-type GaAs was fabricated. The photodetector shows a high photoresponsivity of 0.31 mA·W, a high specific detectivity of0Jones, and a fast response or recovery speed of 117 or 109 ms under the irradiation with the wavelength of 940 nm at zero bias. The results prove that the'-4H-borophene/GaAs photodetector can show high sensitivity and zero consumption, which is of great value in meeting the appeal of sustainable development of society.