P-type and n-type wafers were implanted with phosphorus and boron, respectively, for emitter formation and were annealed subsequently at 950∼1050°C for 30∼90min for activation. Boron emitters were activated at 1000°C or higher, while phosphorus emitters were activated at 950°C. QSSPC measurements show that the implied Voc of boron emitters increases about 15mV and the J01 decreases by deep junction annealing even after the activation due to the reduced recombination in the emitter. However, for phosphorus emitters the implied Voc decreases from 622mV to 560mV and the J01 increases with deep junction annealing. This is due to the abrupt decrease in the bulk lifetime of the p-type wafer itself from 178μs to 14μs. PC1D simulation based on these results shows that, for p-type implanted solar cells, increasing the annealing temperature and time abruptly decreases the efficiency (Δη abs =-1.3%), while, for n-type implanted solar cells, deep junction annealing increases the efficiency and Voc, especially (Δηabs =+0.4%) for backside emitter solar cells.
ASJC Scopus subject areas
- General Chemistry
- Atomic and Molecular Physics, and Optics
- Renewable Energy, Sustainability and the Environment
- General Materials Science