Energy Deposition in a Graphene Field Effect Transistor Based Radiation Detector

The development of high-performance radiation detectors is essential for commercial, scientific, and securityapplications [1]. Due to the unique electronic properties of graphene (high-speed, low-noise), recent radiationdetectors utilize graphene field effect transistors to sense charge carriers produced by radiation interactions in agated semiconductor [2]. A study of the energy deposition due to the transport of gamma rays andelectrons/positrons through typical elemental and compound semiconductors (Si, Ge, GaAs, and CdTe) willallow for a material optimization of these detectors. Geant4, a Monte Carlo based program that simulates thepassage of particles through matter, was used to simulate Compton scattering of gamma rays and multiplescattering of electrons emitted from the decay of Co-60 and Cs-137. The output from Geant4 was a histogramthat displayed the percentage of interactions that deposited energy within set energy bins. Further simulationswill be performed to determine the energy deposition for multiple gamma ray interactions (photoelectric effect,Compton scattering, and pair production) and multiple electron/positron interactions (multiple scattering,ionization, Bremsstrahlung, and e+e-annihilation).KEYWORDSGFET, graphene, semiconductor radiation detector REFERENCES(sample format provided below)[1] M. Foxe et al., “Graphene Field-Effect Transistors on Undoped Semiconductor Substrates for RadiationDetection,” IEEE Trans. Nanotechnol., vol. 11, no. 3, pp. 581-587, May 2012.[2] M. Foxe et al., “Numerical Model of Graphene-Based Radiation Detector Response,” IEEE NSS/MIC, pp.667-670, 2010.