Structural modification and bandgap tunning of cubic AIN thin film by carbon ions irradiations

摘要

This paper deals with the 700 keV energetic Carbon (C) ions irradiations induced structrual modification and optical bandgap tunning of cubic (c) AlN thin films. MOCVD grown c-AlN thin film has been exposed to C ions at various ions fluences of 1 x 10(13), 1 x 10(14) and 1 x 10(15) ions.cm(-2). XRD patterns exhibited that films retain their cubic crystal structure after ions irradiations, indicating their structural stability against irradiation. Full width at half maximum of the XRD peaks remains almost same for pristine and irradiated films. Ions irradiations at fluence of 1 x 10(14) ions/cm(2), produces compressive stresses as observed from the shifts in (220) orientation peaks. However, its pristine position is restored with a further rise of ions fluence to 1 x 10(15) ions/cm(2), thereby relieving the induced stresses. Raman spectra also indicated that the stress produced at lower fluence are recovered with further increase of the fluence. The bandgap obtained from UV-visible optical transmission spectra also modulated with ions dose rate and is changed from 5.88 eV (for as grown) to 5.62 eV at maximum fluence.