Synthesis and characterization of electrospun gallium nitride nanofibers Anamaris Meléndez a , Kristle Morales a , Idalia Ramos *a , Eva Campo b , Jorge J. Santiago-Avilés c a Dept. of Phys. and Electronics, UPR-Humacao, 100 Rd 908, CUH Station, Humacao, PR, 00791 b Dept. of Mat. Science and Eng., Lehigh Univ., 5 East Packer Ave, Bethlehem, PA USA 18015 c Dept. of Elect. and Systems Eng. Univ. of Penn, 200 S 33rd Street, Philadelphia, PA USA 19104 ABSTRACT The simple and inexpensive technique of electrospinning was used for the production of long GaN nanofibers. The fibers were made using a precursor solution composed of pure Gallium Nitrate dissolved in dimethylacetamide (DMA) and a viscous solution of Cellulose acetate dissolved in a mixture of DMA and acetone. Using a tube furnace, they were sintered under a Nitrogen atmosphere to decompose the polymer and to reduce Oxygen contamination. This process was followed by sintering under a NH 3 flow to complete the synthesis of wurtzite GaN. XRD, ESEM, and FTIR analysis were used to verify the chemical and structural composition of the samples. The I-V characteristics of a device constructed using a single GaN nanofiber showed the formation of ohmic contacts. Keywords: GaN, nanofibers, electrospinning, FTIR, XRD, ESEM 1.0 INTRODUCTION One-dimensional nanostructures have attracted attention from researchers due to their interesting physical properties and applications for the development of optoelectronic devices [1-2] . GaN nanowires [3-4] , nanobelts [5] , and other one- dimensional structures have been synthesized and used to construct nanodevices using mostly vapor–liquid–solid (VLS) and vapor–solid (VS) mechanism [6] . In addition to the work done by our group [7] , a recent publication [8] reports the production of electrospun GaN nanofibers using a poly(vinyl pyrrolidone) (PVP) solution Electrospinning [9] is a simple and rapid method that can produce long and continuous fibers in various seconds. In this process, when a high voltage is applied to a precursor solution the electrostatic repulsion overcomes the surface tension and a jet of solution emerges and produces the fibers. The properties of the fibers are controlled by the precursor, voltage, distance between the jet and the collector and ambient conditions. Different shapes of fibers have been produced using this method including nanowires, nanoribbons and nanotubes. Our group has deposited and characterized various types of nanofibers (graphitic carbon, PZT, SnO 2 and Sb:SnO 2 ) , using electrospinning [10-14] . We developed a method for producing GaN nanofibers using electrosinning and a subsequent heating treatment [7, 15] . The precursor solution was prepared using gallium III nitrate hydrate dissolved in dimethylacetamide (DMA). A cellulose acetate polymeric solution was added to the gallium solution until a precursor with the appropriate viscocity for electrospinning was obtained. After electrospinning, the fibers were subjected to a thermal treatment under nitrogen at 400°C to decompose the polymer and the Gallium Nitrate into Ga 2 O 3 . Thermogravimetric/Diferential Thermal Analysis (TG/DTA) on the gallium nitrate precursor was done previously [15] to understand the decomposition of the cellulose acetate and the gallium nitrate to develop a heating plan. The decomposition and dehydration of gallium nitrate before 400°C has been described as [16-17] . 3 2 3 2 2 3 3 6 15 ) 0 9 . ) ( ( 2 HNO O H O Ga H NO Ga + + → (1) Our thermal studies also confirmed the degradation of the cellulose acetate between 260 and 400°C [18] . * iramos@mate.uprh.edu; phone 1 787 850-9381; fax 1 787 850 9308; mate.uprh.edu/~iramos Nanoengineering: Fabrication, Properties, Optics, and Devices VI, edited by Elizabeth A. Dobisz, Louay A. Eldada, Proc. of SPIE Vol. 7402, 740210 · © 2009 SPIE · CCC code: 0277-786X/09/$18 · doi: 10.1117/12.825368 Proc. of SPIE Vol. 7402 740210-1