Midwave infrared (MWIR) is significant for applications such as sensing, imaging, and spectroscopy. Traditional materials in this wavelength range, III-V and II-VI semiconductors, has poor performance due to their high Auger recombination rate and large dark currents. Due to the better properties of black phosphorus (BP) such as its low Auger recombination coefficient, BP-based mid-infrared light emitters and detectors have shown to outperform the state-of-the-art commercial devices. However, the scalability of these devices remains questionable because of the limitations of current BP deposition and growth techniques. Here, we report a BP ink formula which preserves the exceptional properties of BP, to deposit millimeter-scale, uniform and pin-hole free films, which have internal photoluminescence quantum yield of ~0.9%, higher than the III-V and II-VI semiconductors with similar bandgap. Using this ink as a MWIR ‘phosphor’ on a red commercial LED, we demonstrate that a high electroluminescence (EL) external quantum efficiency of ~0.25% can be achieved. We also show that these films can be integrated to heterostructure device architecture with electron and hole selective contacts for both direct emission and detection, achieving EL with external quantum efficiency of ~0.05% and a high photoresponsivity of 47 mA/W at room temperature.
Project currently funded by: Federal