Fast and Broadband Photoresponse of Few-Layer Black Phosphorus Field-Effect Transistors

Abstract

Few-layer black phosphorus, a new elemental 2D material recently isolated by mechanical exfoliation, is a high-mobility layered semiconductor with a direct bandgap that is predicted to strongly depend on the number of layers, from 0.35 eV (bulk) to 2.0 eV (single-layer). Therefore, black phosphorus is an appealing candidate for tunable photodetection from the visible to the infrared part of the spectrum. We study the photoresponse of field-effect transistors (FETs) made of few-layer black phosphorus (3 nm to 8 nm thick), as a function of excitation wavelength, power and frequency. In the dark state, the black phosphorus FETs can be tuned both in hole and electron doping regimes allowing for ambipolar operation. We measure mobilities in the order of 100 cm 2 /V s and current ON/OFF ratio larger than 10 3 . Upon illumination, the black phosphorus transistors show response to excitation wavelengths from the visible up to 940 nm and rise time of about 1 ms, demonstrating broadband and fast detection. The responsivity reaches 4.8 mA/W and it could be drastically enhanced by engineering a detector based on a PN junction. The

Emerging Trends in Phosphorene Fabrication towards Next Generation Devices

“…Apart from its ability to tune the band gap between the valence band and conduction band local extrema, strain also plays a significant role in tuning the effective masses, thereby affecting the exciton anisotropy and binding strength 75. The properties of BP depends on the layer thickness,42 applied strain force,45, 48, 52, 53, 64, 76 stacking order77, 78 and external electric field,79 enabling the realization of devices for different applications such as electronics,35, 37, 80, 81, 82, 83 optoelectronics,84, 85, 86 energy storage,79, 87 saturable absorbers (SA),2, 88, 89, 90, 91, 92 pulsed lasers93, 94, 95 and sensing 96…”

Highly Efficient Infrared Photodetection in a Gate‐Controllable Van der Waals Heterojunction with Staggered Bandgap Alignment

“…Since the graphene photodetector was first implemented in 2009,1 various van der Waals (vdW) materials, such as graphene,1, 2, 3, 4 transition metal dichalcogenides (TMDs),5, 6, 7, 8, 9, 10, 11, 12 and black phosphorus (BP),13, 14, 15 have been utilized to achieve high‐performance photodetectors with high photoresponsivity and a wide detection range. In the early graphene‐based photodetectors, photodetection in a wide range from ultraviolet to terahertz wavelengths was possible, owing to the zero‐bandgap nature of graphene 16.…”

Anomalous doping effect in black phosphorene using first-principles calculations

“…These exotic electronic properties of phosphorene can be utilized for the development of future nanoelectronic devices. [18][19][20] Doping in 2D materials is of fundamental importance to enable a wide range of optoelectronic and electronic devices by tuning their electronic properties. For graphene, it has been well established that carrier concentration can be modulated by charge-transfer doping with adsorbed atoms, molecules, and clusters.…”

“…26 Alternatively, substitutional doping in graphene with heteroatoms provides an effective route for simple and stable tuning of doping levels. Although the electronic properties of pure phosphorene have been extensively studied, [16][17][18][19]21 there are, to our best knowledge, few theoretical and experimental investigations for the effect of various dopants on the electronic properties of phosphorene.In this work, we perform a systematic study of the substitutional doping of phosphorene with group III, IV, V, and VI elements,respectively. Based on first-principles density functional theory (DFT) calculations, we demonstrate that the electronic properties of phosphorene can be tuned depending on the number of valence electrons in dopant atoms: i.e., group IV and VI elements with even number of valence electrons induce a metallic feature, while group III and V elements with odd number of valence electrons preserve the semiconducting feature of pure phosphorene.…”