Positron annihilation and constant photocurrent method measurements on a-Si:H f...

• Author(s): Gordo, P. M. ; Marques, M. F. Ferreira ; Gil, C. Lopes ; Lima, A. P. de ; Lavareda, G. ; Carvalho, C. Nunes de ; Amaral, A. ; Kajcsos, Zs.
• Date: 2007
• Persistent ID: http://hdl.handle.net/10316/4386
• Origin: Estudo Geral - Universidade de Coimbra
• Subject(s): Variable-energy positron annihilation; Doppler broadening; Constant photocurrent method; Defects; Density of states
• Document Type: Article
• Language: English

Description

Defect structure of hydrogenated amorphous silicon thin-films was studied by positron annihilation spectroscopy (PAS), whereas the density of states below the Fermi level was measured by constant photocurrent method (CPM). Divacancies and large vacancy clusters were identified as the main defects present in these films, with relative concentrations strongly dependent on the rf-power. Correlation between PAS, CPM results and I(V) characteristics of solar cells suggests the creation of energy levels above the Fermi energy, not observable by CPM, related to large vacancy clusters. http://www.sciencedirect.com/science/article/B6TVT-4JX373P-2/1/af7c69b0fdf17cefb2432fb357d5d86f