Temperature behaviour of photoluminescence and electron-beam-induced currentrecombination behaviour of extended defects in solar grade silicon

Abstract

The temperature dependence of D-band and band-to-band (BB) luminescencewas measured in EFG samples between 80 K and room temperature fordefects/dislocations presenting different amounts of contamination. Thecontamination density was estimated from the temperature behaviour of theelectron-beam-induced current contrast, ranging between about 104 and 106impurities cm-1 dislocation length. The D1 line became already visible at roomtemperature but its intensity was found to exhibit a maximum at about150 K. D2, D3 and D4 start to show up at about 250, 190 and 170 K,respectively, and increase their intensities upon lowering temperature. At roomtemperature the width of the D1 line is broad and becomes narrowerupon lowering the temperature. D2 shows the opposite behaviour. Theintensities of D1 and D2 were observed to show strong variations across thesample, whereas this was not observed for the pair D4/D3. In particular, theorigin of the lines D1 and D2 is still far from being understood. Twomore lines at 1.040 and 0.987 eV were found in regions where the BBrecombination is strong. They appear without any defect contributionand are explained as phonon replicas of the band edge luminescence.