The dependencies of the BiOi defect concentration on doping, irradiation fluence and particle type in p-type silicon diodes have been investigated. We evidenced that large data scattering occurs for ...fluences above 1012 1 MeV neutrons/cm2, becoming significant larger for higher fluences. We show that the BiOi defect is metastable, with two configurations A and B, of which only A is detected by Deep Level Transient Spectroscopy and Thermally Stimulated Currents techniques. The defect’ electrical activity is influenced by the inherent variations in ambient and procedural experimental conditions, resulting not only in a large scattering of the results coming from the same type of measurement but making correlation between different types of experiments difficult. It is evidenced that the variations in BiOiA are triggered by subjecting the samples to an excess of carriers, by either heating or an inherent short exposure to ambient light when manipulating the samples prior to experiments. For the samples investigated in this work both, the BiOiA as determined from electrical spectroscopic measurements and the full depletion voltage as measured from Current–Voltage characteristics reach a steady state in ∼7h. Any electrical measurement performed before will give a different result. The bi-stable behavior of the BiOi defect fully accounts for these variations.
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•The BiOi defect, causing the acceptor removal process in p-type Si, is bistable.•Only one BiOi configuration is detected by DLTS and TSC -BiOiA(0/+).•The switch between the defect configurations can be triggered by ambient light.•After light exposure, it takes few hours for BiOi to stabilize in a stable state.•The BiOi introduction rate detected in DLTS and TSC experiments is underestimated.
•The electric properties are dependent on the structural quality of AlN films.•The pyroelectric signal generated by AlN is dependent on Si substrate resistivity.•Optical amplification of the signal ...occurs when Si substrate resistivity increases.•The ac conductance has to be used when the electrical time constant is estimated.•The value of the pyroelectric coefficient was found to be around 10–12μCm−2K−1.
Electric and pyroelectric properties of AlN layers deposited on Si substrates with different resistivities were investigated. The dielectric constant was found to be around 12, while the conductance determined from dc current measurements was found to be in the 10−9 to 10−10S range. The pyroelectric measurements were performed in voltage mode using two types of IR sources: a laser diode with 800nm wavelength and a black body at 700°C. A peculiar behavior was observed for the signal recorded when the laser diode was used as IR source. It was found that the Si substrate is introducing a signal component, due to the photogenerated carriers, which is adding to the pyroelectric signal generated by the AlN layer. This component is strongly dependent on the resistivity of the Si substrate. For strongly doped Si (Si++) the signal generated into the substrate represents only 10% of the recorded pyroelectric voltage. For electronic grade Si the signal generated into the substrate is about 100 times larger than the pyroelectric signal generated in the AlN layer. This effect can be used as an optical amplification of the pyroelectric signal. The frequency dependence observed for the pyroelectric signal recorded when the black body is used as IR source is typical for a pyroelectric detector. A value as large as 12.4μCm−2K−1 was obtained for the pyroelectric coefficient using for estimation the constant signal at low modulation frequencies of the IR beam. However, the value of the pyroelectric coefficient is strongly affected by the electrical conductance of the AlN layer. As the conductance is frequency dependent it results that the value of the pyroelectric coefficient is frequency dependent, the value from above being valid only for very small frequencies of the temperature variation. It was also found that the electric and pyroelectric properties are dependent on the crystalline quality of the AlN layer.
A carbon-based layer was deposited by spraying on top of a ferroelectric layer grown by sol-gel on Si (001) substrate and its properties as electrode and absorber for pyroelectric detection were ...tested. It was found that the electric properties of the ferroelectric capacitor with top carbon-based sprayed electrode (CBSE) are comparable with those of the capacitors with standard top SrRuO3 (SRO)/Au electrode. Pyroelectric measurements show that the pyroelectric signal recorded on ferroelectric capacitors with top CBSE electrode is 2.5 times greater than for top SRO/Au electrode for low frequency range. The value of the pyroelectric coefficient was estimated to 9.73·10-4 C/m2K for CBSE electrodes and 3.36·10-4 C/m2K for SRO/Au respectively. The fabrication process of CBSE is of low cost, easy to implement and with high throughput making it attractive for manufacturing various devices like pyroelectric detector, thermal imaging, solar cells, etc.
In this work, the effects of 60Co γ-ray irradiation on high resistivity p-type diodes have been investigated. The diodes were exposed to dose values of 0.1, 0.2, 1, and 2MGy. Both macroscopic (I–V, ...C–V) and microscopic investigations, by means of Thermally Stimulated Current (TSC) and Deep Level Transient Spectroscopy (DLTS) techniques, were conducted to characterize the radiation-induced changes. The investigated diodes were manufactured on high resistivity p-type Float Zone (FZ) silicon and were further classified into two types based on the isolation technique between the pad and guard ring: p-stop and p-spray. After irradiation, the macroscopic results of current–voltage and capacitance–voltage measurements were obtained and compared with existing literature data. Additionally, the microscopic measurements focused on the development of the concentration of different radiation-induced defects, including the Boron interstitial-Oxygen interstitial (BiOi) complex, the Carbon interstitial-Oxygen interstitial (CiOi) defect, the H40K, and the so-called IP∗.
To investigate the thermal stability of induced defects in the bulk, isochronal annealing studies were performed in the temperature range of 100°C to 300°C. These annealing processes were carried out on diodes irradiated with doses of 1 and 2MGy. Furthermore, in order to investigate the unexpected results observed in the C–V measurements after irradiation with high dose values, the surface conductance between the pad and guard ring was measured as a function of both dose and annealing temperature.
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 ...(<inline-formula> <tex-math notation="LaTeX">E_{\text {kin}} </tex-math></inline-formula>) 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-<inline-formula> <tex-math notation="LaTeX">\Omega </tex-math></inline-formula>cm material after irradiation with 23-GeV protons to a fluence of <inline-formula> <tex-math notation="LaTeX">6.91\times 10^{13}\,\,{\text {p/cm}^{2}} </tex-math></inline-formula>. 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 <inline-formula> <tex-math notation="LaTeX">\text{k}\Omega </tex-math></inline-formula>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."
Replacing lead atoms in halide perovskite materials is of significant importance for the development of environmentally friendly perovskite solar cells. In this paper, we investigated the effect of ...doping the MAPbI
2.6
Cl
0.4
hybrid perovskite (MA—methyl ammonium) with non-toxic elements, such as alkaline earth metal ions (Mg
2+
) and transition metal ions (Zn
2+
). The structural, morphological, and optical properties of the prepared samples were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and UV–Vis. spectroscopy. Finally, the doped films were used as photoactive layers in solar devices in order to evaluate their photovoltaic performance. Zn proved to be more appropriate to replace partially Pb and films with higher quality were obtained. As a result, the MAPb1
−
x
Zn
x
I
2.6
Cl
0.4
based solar cells have demonstrated a slight improvement of the photovoltaic performances, resulting in a uniform and narrower PCEs (power conversion efficiency) range, compared to pristine MAPbI
2.6
Cl
0.4
based devices.
Epitaxial thin films of NiFe
2
O
4
are fabricated by pulsed laser deposition on SrTiO
3
substrate. Symmetrical capacitor-like structures are formed using SrRuO
3
as bottom and top electrodes. ...Electrical characterizations, including current–voltage, capacitance–voltage and capacitance–frequency measurement, reveal a hysteresis-like behaviour for current and capacitance as function of voltage. This could be assigned to a resistive and/or capacitive switching. A “degradation” process takes place after repeated voltage cycling or after heating the sample to 400 K, leading to the stabilization of different resistive states. These features can be related to the changes observed in the capacitance–frequency characteristics, suggesting the presence of a relaxation mechanism at low frequencies, and can be associated with the presence of a deep donor-type level in the band-gap of the NiFe
2
O
4
layer.
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•TFTs based on IGZO channel semiconductor and AlN gate dielectric were fabricated.•AlN films – a viable and cheap gate dielectric alternative for transparent TFTs.•Influence of gate ...dielectric layer thickness on TFTs electrical characteristics.•No degradation of AlN gate dielectric was observed during devices stress testing.
The degradation of thin-film transistors (TFTs) caused by the self-heating effect constitutes a problem to be solved for the next generation of displays. Aluminum nitride (AlN) is a viable alternative for gate dielectric of TFTs due to its good thermal conductivity, matching coefficient of thermal expansion to indium–gallium–zinc-oxide, and excellent stability at high temperatures. Here, AlN thin films of different thicknesses were fabricated by a low temperature reactive radio-frequency magnetron sputtering process, using a low cost, metallic Al target. Their electrical properties have been thoroughly assessed. Furthermore, the 200nm and 500nm thick AlN layers have been integrated as gate-dielectric in transparent TFTs with indium–gallium–zinc-oxide as channel semiconductor. Our study emphasizes the potential of AlN thin films for transparent electronics, whilst the functionality of the fabricated field-effect transistors is explored and discussed.
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