Details

Autor(en) / Beteiligte

• Martins, R
• Aguas, H
• Cabrita, A
• Tonello, P
• Silva, V
• Ferreira, I
• Portunato, E
• Guimares, L

Titel

New nanostructured silicon films grown by pecvd technique under controlled powder formation conditions

Ist Teil von

• Solar energy, 2000-01, Vol.69 (SUPPLEMENT), p.263-269

Erscheinungsjahr

2000

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• In this paper the influence of the DC grid bias on the plasma impedance and the I-V behaviour of silane plasmas used to grow undoped amorphous silicon films by plasma enhanced chemical vapour deposition technique using a triode configuration at or close to the powder regime is studied. The aim is to determine the correlation between the r.f. power and the DC grid voltage with the plasma parameters, under isothermal gas conditions. The results should lead to the production of nanostructured films, with the required optoelectronic characteristics for photovoltaic applications. The results achieved show the existence of a boundary region close to the gamma -regime (powder formed) where nanoparticles can be formed by moderated ion bombardment of the growing surface. This is characterised by the plasma resistance of the same order of magnitude of the plasma reactance. Under this condition, it is possible to grow amorphous silicon films that can incorporate nanoparticles, exhibiting photosensitivities of about 10 super(7) (two orders of magnitude larger than the one exhibited by films grown under conventional conditions) with densities of states determined by the constant photocurrent method below 3 x 10 super(15) cm super(.3). Apart from that, the growth of the films is less affected by light soaking than the conventional films grown by standard techniques. copyright 2001 Elsevier Science Ltd. All rights reserved.