In this work, the thermally stimulated current (TSC) technique has been used to investigate the properties of the radiation-induced interstitial boron and interstitial oxygen defect complex by 23-GeV ( $E_{\text {kin}}$ ) protons, including activation energy, defect concentration, as well as the annealing behavior. At first isothermal annealing (at 80 °C for 0–180 min) followed by isochronal annealing (for 15 min between 100 °C and 190 °C in steps of 10 °C), studies had been performed in order to get information about the thermal stability of the interstitial boron and interstitial oxygen defect in 50- $\Omega $ cm material after irradiation with 23-GeV protons to a fluence of $6.91\times 10^{13}\,\,{\text {p/cm}^{2}}$ . The results are presented and discussed. Furthermore, the extracted data from TSC measurements are compared with the macroscopic properties derived from current–voltage and capacitance–voltage characteristics. In addition, the introduction rate of interstitial boron and interstitial oxygen defect as a function of the initial doping concentration was determined by exposing diodes with different resistivities (10, 50, 250, and 2 $\text{k}\Omega $ cm) to 23-GeV protons. These results are compared with data from TSC and deep-level transient spectroscopy measurements achieved by the team of the CERN-RD50 “Acceptor removal project.”

Embedding electronic and optoelectronic devices in common, daily use objects is a fast developing field of research. New architectures are needed for migrating from the classic wafer- based substrates. Novel types of flexible PMMA/Au/Alq ₃ /LiF/Al structures were obtained starting from electrospun polymer fibers. Thus, using an electrospinning process poly (methyl metacrylate) (PMMA) nanofibers were fabricated. A thin Au layer deposition rendered the fiber array conductive, this being further employed as the anode. The next steps consisted of the thermal evaporation of tris(8-hydroxyquinolinato) aluminum (Alq ₃ ) and aluminum deposition as the cathode. The Au covered PMMA nanofiber layer had a similar behavior with an indium tin oxide film i.e. low sheet resistance 10.6 Ω/sq and high transparency. The low electrode resistivities allow an electron drift mobility of about 10 ^–6 cm ² V ⁻¹ s ⁻¹ at a low applied field, similar to the counterpart structures based on thin films. Concerning the relaxation processes in these structures, the Cole–Cole plots exhibit a slightly deformed semicircle, indicating a more complex equivalent circuit for the processes between metal electrodes and the active layer. This equivalent circuit includes reactance equivalent processes at the anode, cathode, in the active layer and most probably originates from the roughness of the metallic electrodes.

The acceptor removal process is the most detrimental effect encountered in irradiated boron-doped silicon. This process is caused by a radiation-induced boron-containing donor (BCD) defect with bistable properties that are reflected in the electrical measurements performed in usual ambient laboratory conditions. In this work, the electronic properties of the BCD defect in its two different configurations (A and B) and the kinetics behind transformations are determined from the variations in the capacitance-voltage characteristics in the 243–308 K temperature range. The changes in the depletion voltage are consistent with the variations in the BCD defect concentration in the A configuration, as measured with the thermally stimulated current technique. The A→B transformation takes place in non-equilibrium conditions when free carriers in excess are injected into the device. B→A reverse transformation occurs when the non-equilibrium free carriers are removed. Energy barriers of 0.36 eV and 0.94 eV are determined for the A→B and B→A configurational transformations, respectively. The determined transformation rates indicate that the defect conversions are accompanied by electron capture for the A→B conversion and by electron emission for the B→A transformation. A configuration coordinate diagram of the BCD defect transformations is proposed.