Position sensitivity of graphene field effect transistors to X-rays

Journal Article · Mon Jun 01 00:00:00 EDT 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4921755· OSTI ID:22415108

Cazalas, Edward; Moore, Michael E.; Jovanovic, Igor ^[1]; Sarker, Biddut K.; Childres, Isaac ^[2]; Chen, Yong P. ^[2]

---

1. Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)
2. Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907 (United States)

Device architectures that incorporate graphene to realize detection of electromagnetic radiation typically utilize the direct absorbance of radiation by graphene. This limits their effective area to the size of the graphene and their applicability to lower-energy, less penetrating forms of radiation. In contrast, graphene-based transistor architectures that utilize the field effect as the detection mechanism can be sensitive to interactions of radiation not only with graphene but also with the surrounding substrate. Here, we report the study of the position sensitivity and response of a graphene-based field effect transistor (GFET) to penetrating, well-collimated radiation (micro-beam X-rays), producing ionization in the substrate primarily away from graphene. It is found that responsivity and response speed are strongly dependent on the X-ray beam distance from graphene and the gate voltage applied to the GFET. To develop an understanding of the spatially dependent response, a model is developed that incorporates the volumetric charge generation, transport, and recombination. The model is in good agreement with the observed spatial response characteristics of the GFET and predicts a greater response potential of the GFET to radiation interacting near its surface. The study undertaken provides the necessary insight into the volumetric nature of the GFET response, essential for development of GFET-based detectors for more penetrating forms of ionizing radiation.

• OSTI ID: 22415108
• Journal Information: Applied Physics Letters, Vol. 106, Issue 22; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
FIELD EFFECT TRANSISTORS
GRAPHENE
IONIZATION
RADIATION DETECTION
RECOMBINATION
SENSITIVITY
SUBSTRATES
X RADIATION