Phototransferred thermoluminescence induced by 525 nm green light in α-Al2O3:C annealed at 1200oC

Abstract

Phototransferred thermoluminescence (PTTL) induced by 525 nm green light in α-Al2O3:C annealed at 1200oC has been studied. The annealing was done to alter the occupancy of electron traps and hole centres within the material. The conventional TL glow curve for measurements made at 1 oC/s shows three peaks at 54, 200, and 324oC labeled PI, PII, and PIII. Whereas the first two peaks are reproduced under phototransfer, the third at 325oC is not. Pulse annealing measurements imply that the PTTL observed at peak PI mainly originates from the electron trap of the dominant peak at 200oC. On the other hand, peak PIII itself is affected by competition effects whereby its charge trap appears to act both as a donor and as an acceptor in competition with electron traps at which PTTL ensues. Measurement of the PTTL of peak II between preheating temperatures of 500 and 650oC suggests that it can be linked, in part, to phototransfer from deep electron traps. PTTL time-response profiles have been formulated as systems of acceptor and donors.