Effects of hydrogen dilution on electron density in multi-hollow discharges with magnetic field for A-Si:H film deposition
We have measured dependence of electron density n<inf>e</inf> on hydrogen dilution ratio R= [H<inf>2</inf>]/([SiH<inf>4</inf>]+[H<inf>2</inf>]) in the multi-hollow discharges with or without magnetic fields to obtain information about the deposition rate enhancement due to hydrogen dilution and applying the magnetic fields. The R dependence of the n<inf>e</inf> did not correlate with that of the deposition rate. The n<inf>e</inf> exponentially decreases with a distance from the discharges z. The n<inf>e</inf> decreases faster for higher R. These complicated behaviors of n<inf>e</inf> may be explained by electron attachment to the clusters generated in the SiH<inf>4</inf>+H<inf>2</inf> discharges. For R=0, the n<inf>e</inf> was almost same value regardless with or without magnetic fields. For R=1, n<inf>e</inf> with magnetic fields was 1/10 of that without magnetic fields. We also found that, for R=0, ne drastically decreased with increasing the z, while for R=1, ne showed a gradual decrease with z. The effects of applying magnetic fields on the deposition are unclear but applying the magnetic fields may affect the electron energy distribution.
On the Way towards High-Efficiency Thin Film Silicon Solar Cells by the "Micromorph" Concept
Note: IMT-NE Number: 222 Reference PV-LAB-CONF-1996-008 Record created on 2009-02-10, modified on 2017-05-10
Compensation of the dangling-bond space charge in amorphous silicon solar cells by graded low-level doping in the intrinsic layer
The compensation of the dangling‐bond space charge in amorphous silicon p‐i‐n solar cells by graded, low‐level doping in the intrinsic layer is discussed and demonstrated experimentally. Carrier collection in p‐i‐n cells without doping indicates that the degraded state space charge is largely positive, and thus that boron doping should be beneficial. Solar cells with linearly decreasing boron doping profiles are shown to yield a homogeneous collection in the intrinsic layer, and a red light conversion efficiency superior to that of undoped cells after light soaking. Also, the optimal doping concentration is shown to be a direct measure of the degraded state defect density.