Determination of Bulk Minority-Carrier Lifetime in BaSi2 Earth-Abundant Absorber Films by Utilizing a Drastic Enhancement of Carrier Lifetime by Post-Growth Annealing

We have successfully determined the bulk minority-carrier lifetime in BaSi 2 epitaxial films by utilizing a drastic enhancement of lifetime by post-growth annealing at 800 °C, which is attributed to strain relaxation. From the film-thickness dependence of lifetime, we reveal that the bulk lifetime i...

Full description

Saved in:
Bibliographic Details
Published inApplied physics express Vol. 6; no. 11; pp. 112302 - 112302-4
Main Authors Hara, Kosuke O, Usami, Noritaka, Nakamura, Kotaro, Takabe, Ryouta, Baba, Masakazu, Toko, Kaoru, Suemasu, Takashi
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.11.2013
Online AccessGet full text

Cover

More Information
Summary:We have successfully determined the bulk minority-carrier lifetime in BaSi 2 epitaxial films by utilizing a drastic enhancement of lifetime by post-growth annealing at 800 °C, which is attributed to strain relaxation. From the film-thickness dependence of lifetime, we reveal that the bulk lifetime is 14 μs, which is long enough for thin-film solar cell applications. In addition, the sum of surface and interface recombination velocities is found to be as low as 8.3 cm/s presumably due to the ionic nature of BaSi 2 . This confirms that BaSi 2 is promising as an absorption-layer material for earth-abundant thin-film solar cells.
Bibliography:Effects of post-growth annealing at 800 °C for 30 s on μ-PCD in 3050-nm-thick BaSi 2 film. The laser intensity used is $1.3\times 10^{5}$ W/cm 2 . Effects of post-growth annealing at 800 °C for 30 s on (a) $\tau_{1/e}$ and (b) lattice parameter ($a$) as a function of BaSi 2 thickness. The laser intensity used is $1.3\times 10^{5}$ W/cm 2 . The blue dotted line represents the reported value for bulk. Apparent carrier lifetime ($\tau_{\text{a}}$) in the 1640- and 2180-nm-thick BaSi 2 films annealed at 800 °C for 30 s as a function of average excess-carrier density ($\Delta n$). The inset shows the minority-carrier decay in the annealed 1640-nm-thick film with an average excess-carrier density of $6.2\times 10^{15}$ cm -2 . Dependence of $1/\tau_{\text{m,eff}}$ on $1/w$.
ISSN:1882-0778
1882-0786
DOI:10.7567/APEX.6.112302