Multilayer 2D germanium phosphide (GeP) infrared phototransistor

Abstract

Layered two-dimensional (2D) materials with broadband photodetection capability have tremendous potential in the design and engineering of future optoelectronics devices. To date, studies of 2D semiconductors are actively focused on graphene, black phosphorus, and black arsenic phosphorus as attractive candidates. So far, however, novel group IV–V 2D semiconductors (e.g., GeAs and SiAs) have not been extensively explored for broad-band optoelectronics applications. Here, we report a high-performance multilayered 2D GeP gate-tunable photodetector that operates at a short-wavelength infrared (SWIR) regime. With a back-gate device geometry, a p-type behavior is observed at room temperature. Furthermore, a broadband spectral response from UV to optical communication wavelengths is detected. Under a nanowatt-level illumination, a peak responsivity of 25.5 A/W at λ = 1310 nm is achieved with detectivity of ∼ 1×1011 cm.Hz1/2.W-1 at a source−drain bias of −5 V and medium gate voltage bias of -30 V. Additionally, the devices show a relatively low dark current of 40-250 nA for device area in the range of 50-600 µm2 and excellent stability and reproducibility. Our work demonstrates the potential of 2D GeP as an alternative mid-infrared material with broad optical tunability suitable for optical communication and low-light-level detection applications.

Planar Multilayered 2D GeAs Schottky Photodiode for High-Performance Visible–Near-Infrared Photodetection

“…Very recently, new, exciting group IV–V 2D compounds (e.g., GeAs and SiAs) have attracted lots of attention due to their unique optoelectronic properties. − This 2D family is closely connected to traditional group IV and group III–V semiconductors compounds. They exhibit tunable band gaps ( E g ) and excellent chemical stability, and their structure asymmetry results in strong electrical and optical anisotropy. − Despite their superior optoelectronic properties, much of the research is focused on theory, − whereas experimental exploration is extremely rare. , …”

Germanium‐based monoelemental and binary two‐dimensional materials: Theoretical and experimental investigations and promising applications

“…286,292 Additionally, a multilayered 2D GeP phototransistor was recently found to be sensitive to broadband spectra from UV to optical communication wavelengths (1310 and 1510 nm), demonstrating its potential as a substitute material for mid-infrared detection with a wide optical tunability appropriate for photocommunication and weak-light detection applications. 383 As we can see from Table 3, the photoresponsivity of 2D Ge-based photodetectors can reach as high as tens A W À1 or even tens of thousands A W À1 , and the detectivities can be 1-4 orders of magnitude higher than that of BP-based photodetector. Therefore, with both high photoresponsivity and dichroic ratios, 2D Ge-based binary materials may be more prominent than BP in the field of next-generation optoelectronic devices with inplane anisotropy.…”

“…The polarization‐direction‐dependent sensitivity of these materials make them suitable candidates for polarization‐based all‐optical switches and polarization‐sensitive photodetection. Furthermore, broadband optical polarization detection can be realized using these Ge‐based binary materials because of their wide range of bandgaps 59,60,367,381–393 . Table 4 presents the performance parameters of these 2D Ge‐based photodetectors.…”

“…In addition, some Ge‐based materials, including GeS 2 and GeSe 2, were shown to be suitable for detecting polarized light in the ultraviolet (UV) region 286,292 . Additionally, a multilayered 2D GeP phototransistor was recently found to be sensitive to broadband spectra from UV to optical communication wavelengths (1310 and 1510 nm), demonstrating its potential as a substitute material for mid‐infrared detection with a wide optical tunability appropriate for photocommunication and weak‐light detection applications 383 …”

“…Furthermore, broadband optical polarization detection can be realized using these Ge-based binary materials because of their wide range of bandgaps. 59,60,367,[381][382][383][384][385][386][387][388][389][390][391][392][393] Table 4 presents the performance parameters of these 2D Ge-based photodetectors.…”