ABSTRACT
Graphene is a highly promising material in the development of new photodetector technologies, in particular due its tunable optoelectronic properties, high mobilities and fast relaxation times coupled to its atomic thinness and other unique electrical, thermal and mechanical properties. Optoelectronic applications and graphene-based photodetector technology are still in their infancy, but with a range of device integration and manufacturing approaches emerging this field is progressing quickly. In this review we explore the potential of graphene in the context of existing single photon counting technologies by comparing their performance to simulations of graphene-based single photon counting and low photon intensity photodetection technologies operating in the visible, terahertz and X-ray energy regimes. We highlight the theoretical predictions and current graphene manufacturing processes for these detectors. We show initial experimental implementations and discuss the key challenges and next steps in the development of these technologies.
ABSTRACT
The probability of secondary electron shake-off in X-ray absorption is calculated using a model form for the time- and energy-dependent core-hole-photoelectron potential, screened by the single plasmon pole dielectric function of the surrounding material. The resultant excitation probabilities are related to the energy-dependent intrinsic loss function in EXAFS data analysis and compared with experiment. Reasonable agreement is obtained close to the absorption edge although the calculation is less accurate at higher photon energies. The theory described allows the losses to be calculated with little computational effort, making the method suitable for routine EXAFS data analysis.
