Effect of Solution Concentration on Optical and Morphological Properties of Gallium Nitride Thin Films

E.S. Alia, b, Wisam J. Aziza, Asmit R. Al-Haddithic aDepartment of Physics, College of Science, Mustansiriyah University, Palestine St., 10052, Baghdad, Iraq bDirectorate General of Education in Diyala, Ministry of Education, Iraq cDepartment of Physics, College of Science, AL Anbar University, AL Anbar, Iraq

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The effects of precursor concentration on the structural, morphological, and optical properties of galium nitride thin films were studied. The films were prepared by depositing solutions with two different precursor concentrations on quartz, p-type Si (100), and porous silicon substrates using the chemical spray pyrolysis technique. Gallium nitrate hydrate (Ga(NO3)3·x H2O) powder dissolved in ethanol was used as the gallium source. Morphological, structural, optical, and spectral properties of the deposited films were characterized by atomic force microscopy, X-ray diffraction, Raman spectroscopy, photoluminescence, and ultraviolet-visable spectrophotometry. The X-ray diffraction results showed a hexagonal structure with orientation normal to the (004) plane. The optical bandgap decreased from 3.17 eV to 3.1 eV when the precursor concentration increased. The results from atomic force microscopy demonstrated that the grain sizes increased from 35 nm to 50 nm when the concentration increased. The root-mean-square also increased, from 9.666 nm to 12.4 nm, as the concentration increased. Blue photoluminescence of gallium nitride was detected in the range from 380 nm to 480 nm and Raman results showed a peak centered at 710 cm-1, consistent with the GaN longitudinal optical phonon A1 of wurtzite structure.

DOI:10.12693/APhysPolA.140.354 topics: chemical spray pyrolysis, gallium nitride