Orientation of the nanocrystallites in AlN thin film determined by FTIR spectroscopy

INERA Conference 2015: Light in Nanoscience and Nanotechnology

Antonova, K.^1 ; Szekeres, A.^1 ; Duta, L.^2 ; Stan, Ge^3 ; Mihailescu, N.^2 ; Mihailescu, In^2,3

Institute of Solid State Physics, Bulgarian Academy of Sciences, Tzarigradsko Chaussee 72, Sofia

1784, Bulgaria^1

National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, Magurele

077125, Romania^2

National Institute of Materials Physics, 105 bis Atomistilor Street, Magurele

077125, Romania^3

关键词: Aluminum nitride (AlN);    Angular dependence;    FTIR spectroscopy;    Grazing incidence X-ray diffraction;    Hexagonal lattice;    Reflectance spectrum;    Resonance frequencies;    Substrate surface;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/682/1/012024/pdf
DOI  :  10.1088/1742-6596/682/1/012024

来源: IOP

【 摘 要 】

Aluminum Nitride (AlN) films were deposited at 450°C in nitrogen ambient at a pressure of 0.1 Pa and at a laser incident fluence of ∼3 J/cm2and pulse repetition rate of 40 Hz. Grazing Incidence X-ray Diffraction patterns evidenced the presence of nanocrystallites in the amorphous AlN matrix. In the FTIR spectra the characteristic Reststrahlen band of AlN crystal with a hexagonal lattice is observed but it is quite broadened (950-550 cm-1). The angular dependence of the reflectance spectra in p-polarised incidence radiation demonstrates the sensitivity of the A1LO phonon mode of the AlN nanocrystallites to their orientation toward the normal to the substrate surface. With decrease of the incidence beam angle the intensity of the A1LO phonon mode diminishes and softening of the resonance frequency occurs.