High performance nanowire based field effect transistors for sensing applications

Field effect transistors are omnipresent electronic devices with applications ranging from microprocessors to biosensors. New and improved architectures are sought with the aim in exploiting functionalities obtained from... [ view full abstract ]

Field effect transistors are omnipresent electronic devices with applications ranging from microprocessors to biosensors. New and improved architectures are sought with the aim in exploiting functionalities obtained from specific composition, morphology or working principles. The development in the field is further fueled by the need of developing devices which shall be used as platforms for smart sensors and exploiting the high surface to volume ratio of low dimensional structures represent a convenient approach.

Nanowires represent a particular case of nanostructures with high aspect ratio and were successfully used as building blocks for the fabrication of electronic devices, including here diodes and transistors.

In the present work we will describe our work regarding the fabrication of nanowire based field effect transistors. Several methods were employed for producing nanowires, wet methods such as electrochemical and chemical and thermal oxidation [1,2]. Each method we employed is low cost and had its own particularities both in terms of advantages and drawbacks. Further the nanowires are harvested and provided with electric contacts by lithographical methods, including here photolithography, electron beam lithography and ion beam induced metallization. When placed on Si/SiO₂ substrates one can use them as gate electrode/gate insulator and a field effect transistor is obtained. Electrical characterization was performed, source drain and gate characteristics being measured. Very high I_on/I_off ratios were measured.

Further functionalization of the nanowire channel field effect transistor leads to the fabrication of very effective sensors. By functionalization the selectivity of the devices can be optimized while the excellent electrical performances lead to increased sensitivity.

[1]      C. Florica, A. Costas, A.G. Boni, R. Negrea, L. Ion, N. Preda, et al., Electrical properties of single CuO nanowires for device fabrication: Diodes and field effect transistors, 106 (2015). doi:10.1063/1.4921914.

[2]      C. Florica, E. Matei, A. Costas, M.E.T. Molares, I. Enculescu, Field Effect Transistor with Electrodeposited ZnO Nanowire Channel, Electrochim. Acta. 137 (2014) 290–297. doi:10.1016/j.electacta.2014.05.124.