Naslov
Modification of thin Si and ZnO films by He ion bombardment  
(Modification of thin Si and ZnO films by He ion bombardment)

Autori
Pentecoste, Lucile ; Meljanac, Daniel ; Ammar, Mohamed-Ramzi ; Bahman, Hakim ; Thomann Anne-Lise ; Gracin, Davor  

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
XXIV. International Materials Research Congress : abstracts / - , 2015

Skup
International Materials Research Congress (24 ; 2015)

Mjesto i datum
Cancún, Meksiko, 16.08.2015. - 20.08.2015

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
He; ion irradiation; nano-Si; Zn

Sažetak
We study the influence of low energy bombardment on the structural and optical properties of thin films using RF excited remote plasma reactor with DC biased substrate holder. The studied thin films were amorphous hydrogenated silicon, a-Si:H, deposited by plasma enhanced chemical vapour deposition and nano-crystalline  ZnO deposited by magnetron sputtering. The ion energy was in the several hundred eV range and calculated penetration depth was few nano meters for both materials. However, the changes caused by ion irradiation were prolonged much deeper in the material.   The structural changes caused by irradiation were analysed by confocal high resolution Raman spectroscopy while optical properties were measured by transmittance and luminescence. Both types  of films showed changes in position of Raman lines that can be ascribed to strain probably caused by He agglomeration in the voids close to surface. The Raman spectra of as deposited ZnO films consisted of low intensity peaks related to characteristic hexagonal structure with addition of peaks that correspond to crystal lattice defects. All of observed lines were broadened and slightly shifted comparing to ideal macroscopic crystal. After irradiation, the peaks related to wurzite crystal structure become dominant indicating improvement of crystal structure while those related to defect in structure remained weak. For a-Si:H, the initial position of TO like peak shifts upon irradiation and the Si-H bond type changed as a consequence of stress induced in material. Irradiated a-Si:H samples show room temperature luminescence, that correspond to Si QD of about 3 nm. This result is interesting since thin Si films that contain quantum dots have many applications in optoelectronic devices and the possibility of such film formation by simple post deposition treatment could have technological relevance in particularly for production of multi layer solar cells.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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