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1

Compensating defect centres in semi-insulating 6H-SiC

Kamiński P., Kozłowski R., Miczuga M., Pawłowski M., Kozubal M., Żelazko J.

Opto-Electronics Review

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2009

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Vol. 17, No. 1

1-7

EN

Photoinduced transient spectroscopy (PITS) has been applied to study electronic properties of point defects associated with charge compensation in semi-insulating (SI) 6H-SiC substrates. The photocurrent relaxation waveforms were digitally recorded in a wide temperature range of 20-800 K and in order to extract the parameters of defect centres, a two dimensional analysis of the waveforms as a function of time and temperature has been implemented. As a result, the processes of thermal emission of charge carriers from defect centres were seen on the spectral surface as the folds, whose ridgelines depicted the temperature dependences of emission rate for detected defect centres. The new approach was used to compare the defect levels in vanadium-doped and vanadium-free (undoped) SI 6H-SiC wafers.

2

Electron traps in Cu(In,Ga)Se2 absorbers of thin film solar cells studied by junction capacitance techniques

Igalson M., Zabierowski P.

Opto-Electronics Review

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2003

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Vol. 11, No. 4

261-267

EN

The results of steady state and transient capacitance spectrocsopy for ZnO/CdS/Cu(In,Ga)Se2 solar cells are presented. A minority carrier signal from the interface region of absorber has been investigated using Laplace-DLTS. Contributions belonging to three discrete electron traps with thermal emission rates distorted by electric field - assisted tunnelling have been identified and assigned to InCu antisite defect. Support for these conclusions has been also provided by admittance spectroscopy of samples in various metastable states created by prolonged exposition to light, voltage bias or elevated temperature. Two other deep electron traps have been revealed by the use of DLTS injection. One of them, tentatively assigned to the VSe defect, is involved in the metastable phenomena observed in Cu(In,Ga)Se2 - based solar cells. Judging from the high value of capture cross section for carriers of both signs we conclude that it might be a dominating recombination centre in these devices.

3

Interaction between pre-existing dislocations in silicon and hydrogen-induced defects introduced by plasma treatment

Milchanin O.V., Gaiduk P.I., Komarov F.F.

Nukleonika

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1999

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Vol. 44, nr 2

175-180

EN

Structural changes in semiconductors caused by hydrogen plasma treatment are the subject of great interest due to passivation of defect levels in the band gap. On the other hand, the reactions between extended and hydrogen-induced defects in silicon are of significant interest for the development of new defect engineering concepts. The experimental results of the interaction among hydrogen-related defects and extended imperfections (dislocations) obtained by ion implantation and annealing are presented in this paper.

PL

Zmiany strukturalne w półprzewodnikach spowodowane obróbką w plazmie wodorowej są przedmiotem dużego zainteresowania z powodu efektu pasywacji poziomów defektowych w przerwie energetycznej. Ponadto oddziaływania między defektami już istniejącymi w krzemie i defektami wywołanymi wodorem są ważne dla rozwoju nowych koncepcji inżynierskich uwzględniających defekty. W pracy przedstawiono wyniki badań doświadczalnych oddziaływania między defektami związanymi z wodorem i uszkodzeniami (dyslokacjami) spowodowanymi implantacją jonową i wygrzewaniem próbek.