Related papers: Photoconductivity of biased graphene
We present a new paradigm for understanding optical absorption and hot electron dynamics experiments in graphene. Our analysis pivots on assigning proper importance to phonon assisted indirect processes and bleaching of direct processes. We…
We directly image hot spot formation in functioning mono- and bilayer graphene field effect transistors (GFETs) using infrared thermal microscopy. Correlating with an electrical-thermal transport model provides insight into carrier…
We report on the observation of terahertz radiation induced edge photogalvanic currents in graphene, which are nonlinear in intensity. The increase of the radiation intensities up to MW/cm$^2$ results in a complex nonlinear intensity…
Recent experiments demonstrated that proton transport through graphene electrodes can be accelerated by over an order of magnitude with low intensity illumination. Here we show that this photo-effect can be suppressed for a tuneable…
Detection of infrared light is central to diverse applications in security, medicine, astronomy, materials science, and biology. Often different materials and detection mechanisms are employed to optimize performance in different spectral…
One of the salient features of graphene is the very high carrier mobility that implies tremendous potential for use in electronic devices. Unfortunately, transport measurements find the expected high mobility only in freely suspended…
We report on noise and thermal conductance measurements taken in order to determine an upper bound on the performance of graphene as a terahertz photon detector. The main mechanism for sensitive terahertz detection in graphene is bolometric…
Ultrafast optical pump-probe spectroscopy measurement on monolayer graphene observes significant optical nonlinearities. We show that strongly photoexcited graphene monolayers with 35 fs pulses quasi-instantaneously build up a broadband,…
We report on the observation of the nonlinear intensity dependence of the bulk photogalvanic current and photoconductivity in the twisted graphene with small twist angles close to the second magical angle. We show that terahertz radiation…
Nonlinear couplings between photons and electrons in new materials give rise to a wealth of interesting nonlinear phenomena. This includes frequency mixing, optical rectification or nonlinear current generation, which are of particular…
Hot electron effects in graphene are significant because of graphene's small electronic heat capacity and weak electron-phonon coupling, yet the dynamics and cooling mechanisms of hot electrons in graphene are not completely understood. We…
We study the origin of photocurrent generated in doped multilayer BP photo-transistors, and find that it is dominated by thermally driven thermoelectric and bolometric processes. The experimentally observed photocurrent polarities are…
Graphene is a promising material for ultrafast and broadband photodetection. Earlier studies addressed the general operation of graphene-based photo-thermoelectric devices, and the switching speed, which is limited by the charge carrier…
Vertical heterostructures of van der Waals materials enable new pathways to tune charge and energy transport characteristics in nanoscale systems. We propose that graphene Schottky junctions can host a special kind of photoresponse which is…
The broadband and ultrafast photoresponse of graphene has been extensively studied in recent years, although the photoexcited carrier dynamics is still far from being completely understood. Different experimental approaches imply either one…
We present a joint theory-experiment study on ultrafast photoluminescence from photoexcited graphene. Based on a microscopic theory, we reveal two distinct mechanisms behind the occurring photoluminescence: Besides the well-known incoherent…
We study the characteristics of photogenerated electron-hole plasma in optically pumped graphene layers at elevated (room) temperatures when the interband and intraband processes of emission and absorption of optical phonons play a crucial…
We report on the observation of photon helicity driven currents in graphene. The directed net electric current is generated in single layer graphene by circularly polarized terahertz laser radiation at normal as well as at oblique incidence…
Thermal conductivity of homogeneous twisted stacks of graphite is found to strongly depend on the misfit angle. The underlying mechanism relies on the angle dependence of phonon-phonon couplings across the twisted interface. Excellent…
We investigated the transient photoconductivity of graphene at various gate-tuned carrier densities by optical-pump terahertz-probe spectroscopy. We demonstrated that graphene exhibits semiconducting positive photoconductivity near zero…