Photoelectrical and optical properties of mixed-dimensional graphene-semiconductor hybrids
Graphene, a 2D van der Waals (vdW) crystal, possesses distinctive electronic, thermal, and optical properties, and robust mechanical strength. There have been more atomically thin materials, including tungsten disulfide, boron nitride, and chromium triiodide. The emergence of both structural and electronic variety in these 2D materials has opened new avenues for scientific studies and functional device designs. The dangling bond free surface of 2D materials is ready to interact with another by vdW forces. Consequently, any 2D material can be integrated with other materials of different dimensionality to form mixed-dimensional heterostructures.
Graphene phototransistors
While previous works for graphene-based photodetectors focused on local photoresponse by illuminating at the location of a device, one of the highlights from this study is the observation of a nonlocal high-responsivity photo-response even when the SiC substrate is illuminated at distances of several hundred micro-meters from the graphene (right figure). For light illumination within ~100 mm of the graphene, the device shows a strong photo-current signal with a room temperature photo-responsivity exceeding ~10 A/W (reaching ~18 A/W when the illumination is on the graphene). We also found that the photoresponse of the graphene phototransistor is wavelength-dependent.
​
B. K. Sarker*, E. Cazalas*, T. F. Chung* et al., Nature Nanotechnology 12, 668 (2017)
