Charge-carrier trapping levels

The electrical current of a coplanar interdigital gold/LPPP/gold device is space charge limited due to 79-type charge carrier traps localized in the bandgap [28], This can be inferred from the field dependence of the dark current at room temperature. The thermally stimulated current spectrum exhibits two peaks, corresponding to two distinct trap levels , and, which can be calculated from the rise in current, I, below the peak temperature ... 

The properties of energetically-distributed charge-carrier traps are above all in disordered organic semiconductors of considerable significance for the analysis of real current-voltage characteristics. We consider the following two energy distributions for shallow traps an exponential distribution, with its maximum at the transport level Ee (compare Fig. 8.6) ... 

Dorenbos P (2009) Lanthanide charge transfer energies and related luminescence, charge carrier trapping, and redox phenomena. J Alloys Compd 488 568-573 Dorenbos P (2004) Locating lanthanide impurity levels in the forbidden band of host crystals. J Lumin 108 301-305... 

All other experimental TSR techniques used in trap level spectroscopy in semiconductors (insulators) are indirect methods for the determination of trapping parameters. The techniques involve the measurement of phenomena that are due to charge carriers emitted after thermal stimulation from the traps. 

This experimental method, as well as the formal kinetics of the process, is closely related to trap level spectroscopy by thermally stimulated release of trap charge carriers. 

This section contains a review of results on the extensive study of defect states in the mobility gap of amorphous As- and Sb-containing chalcogenide semiconductors by relaxation technique. For extracting typical features, elemental selenium and simple compositions with relatively low content of arsenic and antimony are exemplified as possible. We will try to attribute TSDC peaks to charge carriers released from the respective trapping levels in the band gap of these materials. 

Here, the responses are normalized to the maximum concentration r>o of excitations. The signal evolution in a bi-exponential decay is therefore n(t) = Ani(t) + Bn2(t), where A and B are proportional to the radiative (or non-radiative) rates of the two levels. For solids, a monoexponential PL decay can be explained by the thermally activated recombination of highly mobile electrons and holes trapped onto radiative defects. Such a mechanism requires that the spatial separation of the trapped charge carriers be small. 

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