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Thermally stimulated time-of-flight experiments (abstract)
Synthetic Metals, 37 (1990) 357
357
THERMALLY STIMULATED TIME-OF-FLIGHT EXPERIMENTS (ABSTRACT) I. GLOWACKI a*, J. ULAlqSKI% J. S I E I ~ K I b and M. KRYSZEWSKI a
aPolymer Institute, Technical University of Ldd~,, 90-924 Ldd~ (Poland) bCentre of Molecular and Macromolecular Studies of the Polish Academy of Science, 90-363 LSd2 (Poland)
Thermally stimulated currents (TSC) and thermoluminescence (TL) techniques are commonly used to investigate trapping phenomena in semiconductors and insulators. Simultaneous TSC and TL experiments carried out on a photoconducting mixture of polycarbonate with poly(N-vinylcarbazole) enable us to show that while the TL spectra reveal information on the trapping/detrapping processes, the position and the shape of the TSC peak is controlled by charge-carrier transport across the sample (the so-called 'transport peak'). In the present paper, we demonstrate that the TSC measurements can be regarded as thermally stimulated time-of-flight (TOF) experiments, if at the beginning of the TSC experiment the charge carriers are generated in the vicinity of the front electrode only (e.g. by strongly absorbed light) and at a temperature low enough to immobilize the photogenerated electron/hole pairs. We have found that the position of the TSC peak shifts towards lower temperatures with increasing external electric field, in accordance with the predictions of the theoretical model. The TOF experiments, using an electron beam, were carried out for the same samples at different temperatures, also in the range where the TSC maximum is observed. Direct comparison of the TSC spectra and of the isothermal TOF measurements also confirms the proposed interpretation.
Acknowledgement This work was supported by CPBP 01.12.
*Author to whom correspondence should be addressed. 0379-6779/90/$3.50
© Elsevier Sequoia/Printed in The Netherlands
357
THERMALLY STIMULATED TIME-OF-FLIGHT EXPERIMENTS (ABSTRACT) I. GLOWACKI a*, J. ULAlqSKI% J. S I E I ~ K I b and M. KRYSZEWSKI a
aPolymer Institute, Technical University of Ldd~,, 90-924 Ldd~ (Poland) bCentre of Molecular and Macromolecular Studies of the Polish Academy of Science, 90-363 LSd2 (Poland)
Thermally stimulated currents (TSC) and thermoluminescence (TL) techniques are commonly used to investigate trapping phenomena in semiconductors and insulators. Simultaneous TSC and TL experiments carried out on a photoconducting mixture of polycarbonate with poly(N-vinylcarbazole) enable us to show that while the TL spectra reveal information on the trapping/detrapping processes, the position and the shape of the TSC peak is controlled by charge-carrier transport across the sample (the so-called 'transport peak'). In the present paper, we demonstrate that the TSC measurements can be regarded as thermally stimulated time-of-flight (TOF) experiments, if at the beginning of the TSC experiment the charge carriers are generated in the vicinity of the front electrode only (e.g. by strongly absorbed light) and at a temperature low enough to immobilize the photogenerated electron/hole pairs. We have found that the position of the TSC peak shifts towards lower temperatures with increasing external electric field, in accordance with the predictions of the theoretical model. The TOF experiments, using an electron beam, were carried out for the same samples at different temperatures, also in the range where the TSC maximum is observed. Direct comparison of the TSC spectra and of the isothermal TOF measurements also confirms the proposed interpretation.
Acknowledgement This work was supported by CPBP 01.12.
*Author to whom correspondence should be addressed. 0379-6779/90/$3.50
© Elsevier Sequoia/Printed in The Netherlands