Breaking the Cut‐Off Wavelength Limit of GaTe through Self‐Driven Oxygen Intercalation in Air

Abstract

Low symmetric two dimensional (2D) semiconductors are of great significance for their potential applications in polarization‐sensitive photodetection and quantum information devices. However, their real applications are limited by their photo‐detecting wavelength ranges, which are restricted by their fundamental optical bandgaps. Recently, intercalation has been demonstrated to be a powerful strategy to modulate the optical bandgaps of 2D semiconductors. Here, the authors report the self‐driven oxygen (O2) intercalation induced bandgap reduction from 1.75 to 1.19 eV in gallium telluride (GaTe) in air. This bandgap shrinkage provides the long‐wavelength detection threshold above ≈1100 nm for O2 intercalated GaTe (referred to as GaTeO2), well beyond the cut‐off wavelength at ≈708 nm for pristine GaTe. The GaTeO2 photodetectors have a high photoresponsivity, and highly anisotropic photodetection behavior to even sub‐waveband radiation. The dichroic ratio (Imax/Imin) of photocurrent is about 1.39 and 2.9 for 600 nm and 1100 nm, respectively. This findings demonstrates a broadband photodetector utilizing GaTe after breaking through its bandgap limitation by self‐driven O2 intercalation in air and further reveal its photoconductivity anisotropic nature. This provides design strategies of 2D materials‐based high‐performance broadband photodetectors for the exploration of polarized state information.

Broadband Photodetection of Centimeter-Scale T-Phase Gallium Telluride Grown by Molecular Beam Epitaxy

“…On the other hand, the device under ultraviolet light exhibited high responsivity but slow photoresponse kinetics (Figure S5 in the Supporting Information). Additionally, it is noteworthy that the photodetector exhibits a fast and clear response at 1064 nm, much longer than the detection wavelength of pristine m-GaTe and h-GaTe devices. , This result shows that the response of untreated T-GaTe in the NIR region is comparable to that of oxygen intercalation GaTe devices, which holds great significance in broadband photodetection. To further evaluate the photoresponse characteristics of the device across the visible to NIR range, current–voltage ( I–V) curves were measured in the dark and under different laser illuminations, as shown in Figure e.…”

Enhanced Interlayer Charge Injection Efficiency in 2D Multilayer ReS2 via Vertical Double-Side Contacts

“…In addition, the observed similar W•R CT range of TC and BC of our ReS 2 devices with a pseudo ohmic behavior indicates a negligible contact quality difference between them (see Figure S5 in the Supporting Information and Figure 2a). The estimated contact resistivity of highperformance 2D optoelectronic devices would be greatly reduced by combining numerous reported surface treatment methodologies, 38−40 oxygen intercalation, 41 and hybridization of energy bands with VDC. 42 These findings provide a clear insight into the increasing importance of the location of the channel centroid and contact electrode.…”

High Performance Graphene–C60–Bismuth Telluride–C60–Graphene Nanometer Thin Film Phototransistor with Adjustable Positive and Negative Responses

“…[7][8][9] Since Xia et al prepared the first graphene phototransistor in 2009, [10] graphene has been used in hybrid systems with various materials or even physical local fields to achieve photoelectric detection. [11] For example, metasurfaces, [12][13][14] quantum dots (QDs), [15] nanowires, [16,17] bulk materials, [18] transition metal dichalcogenide materials, [19,20] perovskite materials, [21][22][23] and various organic substances [24][25][26] have been combined with graphene to achieve a high performance photoelectric detection. [27] These works have extensively promoted the research progress of graphene in the field of photoelectric detection.…”