title: Isolated photosystem I reaction centers on a functionalized gated high electron mobility transistor.
abstract: In oxygenic plants, photons are captured with high quantum efficiency by two specialized reaction centers (RC) called Photosystem I (PS I) and Photosystem II (PS II). The captured photon triggers rapid charge separation and the photon energy is converted into an electrostatic potential across the nanometer-scale (~6 nm) reaction centers. The exogenous photovoltages from a single PS I RC have been previously measured using the technique of Kelvin force probe microscopy (KFM). However, biomolecular photovoltaic applications require two-terminal devices. This paper presents for the first time, a micro-device for detection and characterization of isolated PS I RCs. The device is based on an AlGaN/GaN high electron mobility transistor (HEMT) structure. AlGaN/GaN HEMTs show high current throughputs and greater sensitivity to surface charges compared to other field-effect devices. PS I complexes immobilized on the floating gate of AlGaN/GaN HEMTs resulted in significant changes in the device characteristics under illumination. An analytical model has been developed to estimate the RCs of a major orientation on the functionalized gate surface of the HEMTs.
authors.affiliation: Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, TN 37996, USA. saziaeliza@gmail.com
authors.forename: Sazia A
authors.initials: SA
authors.lastname: Eliza
authors.forename: Ida
authors.initials: I
authors.lastname: Lee
authors.forename: Fahmida S
authors.initials: FS
authors.lastname: Tulip
authors.forename: Salwa
authors.initials: S
authors.lastname: Mostafa
authors.forename: Elias
authors.initials: E
authors.lastname: Greenbaum
authors.forename: M Nance
authors.initials: MN
authors.lastname: Ericson
authors.forename: Syed K
authors.initials: SK
authors.lastname: Islam
mesh_terms: D000535:Aluminum / Q000737:chemistry; D015374:Biosensing Techniques; D004583:Electrons; D005708:Gallium / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D008623:Mercaptoethanol / Q000737:chemistry; D018625:Microscopy, Atomic Force; D009584:Nitrogen / Q000737:chemistry; D017785:Photons; D045331:Photosystem I Protein Complex / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D014173:Transistors, Electronic
chemical_list: D045331:Photosystem I Protein Complex; D008623:Mercaptoethanol; D006046:Gold; D005708:Gallium; D000535:Aluminum; D009584:Nitrogen