Intensity dependence of quantum efficiency and photo-gating effects in thin film silicon solar cells. / Reynolds, Steve; Main, Charles; Smirnov, Vladimir; Meftah, Amjad.
Physica Status Solidi C - Current Topics in Solid State Physics, Vol 7 No 3-4. ed. / REI Schropp. Weinheim : Wiley-V C H Verlag GMBH, 2010. p. 505-508.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
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TY - CHAP
T1 - Intensity dependence of quantum efficiency and photo-gating effects in thin film silicon solar cells
A1 - Reynolds,Steve
A1 - Main,Charles
A1 - Smirnov,Vladimir
A1 - Meftah,Amjad
AU - Reynolds,Steve
AU - Main,Charles
AU - Smirnov,Vladimir
AU - Meftah,Amjad
PB - Wiley-V C H Verlag GMBH
CY - Weinheim
PY - 2010
Y1 - 2010
N2 - <p>Steady-state photoconductivity measurements have been carried out on thin-film silicon pin structures of i-layer thickness typically 4 mu m, where crystalline composition has been varied by adjustment of the silane concentration in the process gas. In amorphous and low-crystallinity cells, strongly-absorbed light incident from the p-side at photon fluxes in excess of 10(14) cm(-2) s(-1) produces strongly sub-linear intensity dependence, 'S' shaped reverse current-voltage curves and amplification of a second weakly-absorbed beam, termed photogating. These effects are linked to the formation of space charge and attendant low-field region close to the p-i interface, as confirmed by computer simulation. More crystalline devices exhibit little or no such behaviour. At lower intensities of strongly-absorbed light there is a markedly steeper increase in reverse current vs. voltage in low-crystalline when compared to amorphous cells, particularly with light incident from the n-side. This suggests the mobility-lifetime product for holes is much larger in the former case, consistent with the higher hole mobilities reported in time of flight studies. Thus the prospect of composition-dependent changes in mobility as well as defect density should be borne in mind when developing materials for application in microcrystalline silicon solar cells. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim</p>
AB - <p>Steady-state photoconductivity measurements have been carried out on thin-film silicon pin structures of i-layer thickness typically 4 mu m, where crystalline composition has been varied by adjustment of the silane concentration in the process gas. In amorphous and low-crystallinity cells, strongly-absorbed light incident from the p-side at photon fluxes in excess of 10(14) cm(-2) s(-1) produces strongly sub-linear intensity dependence, 'S' shaped reverse current-voltage curves and amplification of a second weakly-absorbed beam, termed photogating. These effects are linked to the formation of space charge and attendant low-field region close to the p-i interface, as confirmed by computer simulation. More crystalline devices exhibit little or no such behaviour. At lower intensities of strongly-absorbed light there is a markedly steeper increase in reverse current vs. voltage in low-crystalline when compared to amorphous cells, particularly with light incident from the n-side. This suggests the mobility-lifetime product for holes is much larger in the former case, consistent with the higher hole mobilities reported in time of flight studies. Thus the prospect of composition-dependent changes in mobility as well as defect density should be borne in mind when developing materials for application in microcrystalline silicon solar cells. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim</p>
U2 - 10.1002/pssc.200982893
DO - 10.1002/pssc.200982893
M1 - Conference contribution
SN - *****************
BT - Physica Status Solidi C - Current Topics in Solid State Physics, Vol 7 No 3-4
T2 - Physica Status Solidi C - Current Topics in Solid State Physics, Vol 7 No 3-4
A2 - Schropp,REI
ED - Schropp,REI
SP - 505
EP - 508
ER -