Characterization of the Initial Rapid Decay on Light-Induced Carrier Lifetime and Cell Performance Degradation of Czochralski-Grown Silicon

Abstract

The rapid initial degradation of Czochralski-grown silicon (Cz-Si) solar cell performance has been investigated. The initial rapid degradation occurs at the beginning of the degradation process and is followed by a second slower degradation. The surface effect due to interface state degradation between the passivation layer and the Si substrate was investigated on several kinds of Cz-and float zone Si (FZ-Si) wafers. Carrier lifetime degradation induced by an illumination for 30 s was observed on every Cz-Si wafer, but no degradation was observed on FZ-Si wafers. Moreover, only the decrease of IR response of a cell was observed as a result of the initial degradation. The results suggest that the degradation occurs in the bulk. The magnitude and decay time of the degradation appear to depend on the wafer resistivity. Defects very similar to boron-oxygen complexes specific to Cz-Si were considered to be responsible. The distinctly small activation energy of 0.19 eV was obtained for the initial degradation, which suggests a fundamentally different defect reaction process. The activation energy of 1.6 eV for the defect annihilation process was obtained for both defects as well.

Forward current enhanced elimination of the radiation induced boron-oxygen complex in silicon n+ -p diodes

“…Another process where boron–oxygen interaction plays an important role is the light‐induced degradation of Si solar cells. This process is characterized by much lower activation energies, one initial fast process with an activation energy around 0.2 eV followed by a slow degradation process with activation energies between 0.4 and 0.5 eV . It was suggested that the degradation is associated with the formation of boron–oxygen dimer centers (B i O 2i or B s O 2i ) .…”

Ab-initio calculation study on the formation mechanism of boron-oxygen complexes in c-Si

“…In contrast, the ξ(C i O i + ) is nearly identical to the ξ(O 2i + ) since the similar charged supercells should have the similar defect-defect interactions in the CASTEP code, then the ξ term can be offset in MM calculation as shown in Eq. (4). So the energy levels of O 2i and B s O 2i with better accuracy can be expected by using the marker method.…”

Local activation of light-induced degradation in co-doped boron-phosphorus silicon: Evidence of defect diffusion phenomena

“…Light-induced degradation (LID) has received considerable attention in recent years due to its detrimental impact on the performance of photovoltaic (PV) solar cells under field conditions [1]. Several studies investigating this effect have been published and introduced various trends and interpretations [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. LID phenomenon was firstly presented in 1973 by Fischer and Pschunder [2]; they observed a significant degradation of the efficiency of Cz-based silicon solar cells under illumination.…”