Light trapping by formation of nanometer diameter wire-like structures on mu c-Si thin films

Citation
J. Rappich et al., Light trapping by formation of nanometer diameter wire-like structures on mu c-Si thin films, J NON-CRYST, 266, 2000, pp. 284-289
Citations number
15
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF NON-CRYSTALLINE SOLIDS
ISSN journal
00223093 → ACNP
Volume
266
Year of publication
2000
Part
A
Pages
284 - 289
Database
ISI
SICI code
0022-3093(200005)266:<284:LTBFON>2.0.ZU;2-F
Abstract
The electrochemical formation of porous silicon (PS) layers on microcrystal line silicon (mu c-Si) thin films in HF-based solutions was investigated. T he thickness of such PS-layers is as small as 50 nm which we suggest may ha ve application in light trapping structures for Si solar cells. The integra ted reflectance in the visible spectral region was reduced to less than 10% , depending on the etching conditions for PS-formation. Scanning electron m icroscopy reveals a nanometer size wire-like structure. The photoluminescen ce (PL) intensity increases and the PL maximum shifts to longer wavelength with increasing length of the wires. in addition, electron microscopy shows that the volume of the crystallites is preferentially etched but not the g rain boundaries. This etching effect point to a potential loss across or al ong these grain boundaries which reduces the etching rate, thus leading to the wire-like structure. (C) 2000 Elsevier Science B.V. All rights reserved .