We present a measurement of the energies and capture cross-sections of defect states in methylammonium lead bromide (MAPbBr 3 ) single crystals. Using Laplace current deep level transient spectroscopy (I-DLTS), two prominent defects were observed with energies 0.17 eV and 0.20 eV from the band edges, and further I-DLTS measurements confirmed that these two defects are bulk defects. These results show qualitative agreement with theoretical predictions, whereby all of the observed defects behave as traps rather than as generation-recombination centers. These results provide one explanation for the high efficiencies and open-circuit voltages obtained from devices made with lead halide perovskites. Published by AIP Publishing. https://doi.

The influence of high energy electron (HEE) irradiation from a Sr-90 radio-nuclide on n-type Ni/4H-SiC samples of doping density 7.1 × 10 15 cm -3 has been investigated over the temperature range 40-300 K. Currentvoltage (I-V), capacitance-voltage (C-V) and deep level transient spectroscopy (DLTS) were used to characterize the devices before and after irradiation at a fluence of 6 × 10 14 electrons-cm -2 . For both devices, the I-V characteristics were well described by thermionic emission (TE) in the temperature range 120 -300 K, but deviated from TE theory at temperature below 120 K. The current flowing through the interface at a bias of 2.0 V from pure thermionic emission to thermionic field emission within the depletion region with the free carrier concentrations of the devices decreased from 7.8 × 10 15 to 6.8 × 10 15 cm -3 after HEE irradiation. The modified Richardson constants were determined from the Gaussian distribution of the barrier height across the contact and found to be 133 and 163 Acm −2 K −2 for as-deposited and irradiated diodes, respectively. Three new defects with energies 0.22, 0.40 and 0.71 eV appeared after HEE irradiation. Richardson constants were significantly less than the theoretical value which was ascribed to a small active device area.

a b s t r a c tTemperature dependent current-voltage (I-V) and capacitance-voltage (C-V) measurements have been performed on Pd/ZnO Schottky barrier diodes in the range 60-300 K. The room temperature values for the zero bias barrier height from the I-V measurements (F I-V ) was found to be 0.52 eV and from the C-V measurements (F C-V ) as 3.83 eV. From the temperature dependence of forward bias I-V, the barrier height was observed to increase with temperature, a trend that disagrees with the negative temperature coefficient for semiconductor material. The C-V barrier height decreases with temperature, a trend that is in agreement with the negative temperature coefficient of semiconductor material. This has enabled us to fit two curves in two regions (60-120 K and 140-300 K). We have attributed this behaviour to a defect observed by DLTS with energy level 0.31 eV below the conduction band and defect concentration of between 4 Â 10 16 and 6 Â 10 16 cm À 3 that traps carriers, influencing the determination of the barrier height.

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