Long operating lifetime mid-infrared LEDs based on black phosphorus

Abstract

Black phosphorus (BP) is a narrow bandgap layered semiconductor promising for mid-infrared optoelectronic applications. BP-based devices have been shown to surpass state-of-the-art mid-infrared detectors and light-emitting diodes (LEDs) in terms of performance. Despite their device advantages, the material’s inherent instability in the air could hinder its use in practical optoelectronic applications. Here, we investigated the impact of passivation on the device lifetime of BP LEDs, which deteriorate in a matter of seconds without using passivation. The lifetime is significantly extended with an Al2O3 passivation layer and nitrogen packaging via atomic layer deposition and ultra-violet curable resin sealing. The operational lifetime (half-life) at room temperature is extrapolated to be ~15,000 h with an initial power density of 340 mW/cm2 based on accelerated life testing. The present results indicate that efficient BP optoelectronics can be highly robust through simple and scalable packaging technologies, with important practical implications for mid-infrared applications.

Multicolor Inks of Black Phosphorus for Midwave‐Infrared Optoelectronics

“…This is probably because of the degradation of thinner bP particles, which is relatively more unstable than bulk bP (>50 nm). [28,35] The epoxy passivation is scalable, and its thermal budget is relatively lower than the oxide passivation via atomic layer depositions that operated at 150-200 °C, commonly used for a passivation layer for bP flakes. [35,36] This approach is com-patible with a variety of substrates, making it suitable for scalable applications.…”

Mid-Infrared Light-Emitting Diodes Based on Black Phosphorus with Asymmetric Electrodes

“…In addition, electron–hole pairs (or excitons for thin layers) in BP have a low Auger recombination coefficient, offering the prospect for application in infrared optoelectronics. The reported BP-based mid-infrared LEDs are mainly typical p–n junctions such as BP/MoS 2 heterostructure. − Thin-layer MoS 2 is used as the n-region of electron conduction and BP is used as the p-region of hole conduction at positive bias . These types of p–n junction devices face the challenges of scalability, and the carrier injection scenario is sensitive to the thicknesses of the chosen flakes.…”

Mid-Infrared, Optically Active Black Phosphorus Thin Films on Centimeter Scale

“…This distinctive crystal structure imparts a strong in-plane anisotropy across electronic, thermoelectric, and optical properties, , facilitating highly sensitive bandgap modulation through lattice strain, and maintaining a low Auger recombination rate . Photonic devices of remarkable performance have been demonstrated with exfoliated BP flakes, showcasing features such as high detectivity ( D * > 10 10 cm Hz 1/2 W –1 ) at room temperature (RT); − widely tunable light sources covering wavelengths from 2.3 to 7.7 μm by applying strain or electric fields; , and light-emitting diodes (LEDs) with a long operational lifetime (15,000 h half-life) . Despite its considerable promise for next-generation infrared (IR) devices, surpassing existing technologies based on II–VI or III–V semiconductors (e.g., InSb, HgCdTe), the large-scale implementation of BP thin films has faced impediments due to the absence of chip-to-wafer scale thin film growth, , setting it apart from other van der Waals materials like graphene, h -BN, and transition-metal dichalcogenides (MoS 2 , WSe 2 ). − This limitation arises from less controllable lateral growth, influenced by large surface energies and robust interlayer forces stemming from sp 3 hybridization, featuring a lone-pair in BP’s puckered structure. , …”