Fig. 2: Graphene/hBN heterostructure phototransistor in the linear regime.
a Linear photocurrent–bias characteristics measured at low bias for low incident power ranging from 0.1 to 1 mW. The measurements are performed at the CNP for a temperature of 4 K. The polarization of the incident light is linear, parallel to the dc electric field. b From photocurrent measurements and electrical characterization, we extract the photocarrier density and carrier lifetime as a function of the incident power in this low-bias regime, assuming negligible carrier multiplication effect (M = 1). Considering the layered geometry of our device and the size of the sample, the absorbed power Pabs = 6.8686 × 10−4 × Pinc. c Responsivity and internal quantum efficiency (IQE) of the graphene/hBN heterostructure phototransistor as a function of \(V_{{\rm{DS}}}^ \ast\). d Ratio between the photocurrent measured when light polarization is perpendicular to the dc electric field over the photocurrent when light polarization is parallel to the dc electric field as a function of Pinc. e Sketch of the dominating relaxation and recombination processes: intraband electron–electron scattering and interband Auger recombination.
