ABSTRACT
This study investigates the beta irradiation's impact on the electrical features of interfacial nanostructures composed of poly(vinyl alcohol) (PVA) doped with graphene. The integration of graphene, a 2D carbon allotrope renowned for its exceptional electrical conductivity, into PVA nanostructures holds significant promise for advanced electronic applications. Beta irradiation, as a controlled method of introducing radiation, offers a unique avenue to modulate the properties of these nanostructures. Therefore, this study examines the Au/3% graphene(Gr)-doped PVA/n-type Si structure with and without beta (ß) radiation. The effect of beta radiation on the electrical properties of the Au/3% graphene(Gr)-doped PVA/n-type Si structure has been researched by utilizing the current-voltage (I-V) data. The studied structures were exposed to a 90Sr ß-ray source at room temperature to show the effect of beta radiation. The series resistance (R s), shunt resistance (R sh), ideality factor (n), barrier height (BH) (ΦB0), and saturation current (I o) were computed using the I-V data after 90Sr ß-ray irradiation (0, 6, and 18 kGy) and before using the thermionic emission, Norde, and Cheung methods. The BH, ideality factor, and series resistance were calculated using the I-V data as follows: 0.888 eV, 3.21, and 5.25 kΩ for 0 kGy; 0.782 eV, 5.30, and 3.47 for 6 kGy; 0.782 eV, 5.46, and 2.63 kΩ for 18kGy. The BH, ideality factor, and series resistance were also calculated using the Cheng Methods, and the following results were found respectively: 7.22, 0.74, and 3.97 kΩ (Cheng I), and 3.22 kΩ (Cheng II) for 0 kGy; 5.14, 0.813, and 2.72 kΩ (Cheng I), and 2.14 kΩ (Cheng II) for 6 kGy; 6.78, 0.721, and 1.96 kΩ (Cheng I), 1.64 kΩ (Cheng II) for 18 kGy. The BH and series resistance were defined as 0.905 and 16.12 kΩ for 0 kGy, 0.859 and 5.31 kΩ for 6 kGy, and 0.792 and 2.49 kΩ for 18 kGy, respectively. Interface states density (N ss) as a function of E c-E ss was also attained by taking into account the voltage dependence of n, ΦB, and R s. Experimental results showed that the values of n and N ss increased with an increase in the ß-ray radiation dose. On the other hand, the saturation current (I o), ΦB0, and R s values decreased with the increase in the ß-ray radiation dose. The obtained results indicate a nuanced interplay between ß irradiation dose and the nanostructure's overall electrical properties. Insights gained from this study contribute to the understanding of radiation-induced effects on graphene-doped polymer nanostructures, providing valuable information for optimizing their performance in electronic applications.
ABSTRACT
Lanthanides are largely used in optoelectronics as dopants to enhance the physical and optical properties of semiconducting devices. In this study, lanthanum(III)hydroxide nanoparticles (La(OH)3NPs) are used as a dopant of polyethylenimine (PEI)-functionalized nitrogen (N)-doped graphene quantum dots (PEI-NGQDs). The La(OH)3NPs-dopedPEI-NGQDs nanocomposites are prepared from La(NO)3 in a single step by a green novel method and are characterized by Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Deposited over an n-type Si wafer, the La(OH)3NPs-dopedPEI-NGQDs nanocomposites form Schottky diodes. The I-V characteristics and the photoresponse of the diodes are investigated as a function of the illumination intensity in the range 0-110 mW cm-2 and at room temperature. It is found that the rectification ratio and ideality factor of the diode decrease, while the Schottky barrier and series resistance increase with the enhancing illuminations. As a photodetector, the La(OH)3NPs-dopedPEI-NGQDs/n-Si heterojunction exhibits an appreciable responsivity of 3.9 × 10-3 AW-1 under 22 mW cm-2 at -0.3 V bias and a maximum detectivity of 8.7 × 108 Jones under 22 mW cm-2 at -0.5 V. This study introduces the green synthesis and presents the structural, electrical, and optoelectronic properties of La(OH)3NPs-dopedPEI-NGQDs, demonstrating that these nanocomposites can be promising for optoelectronic applications.
ABSTRACT
In this study, poly(2-ethylhexyl acrylate) (PEHA) homopolymer and its copolymer combined with acrylic acid P(EHA-co-AA) were employed as interfaces in two separate Schottky structures. First, both interfaces were grown by initiated chemical vapor deposition (iCVD), which provides much better deposition control and homogeneous coating compared to solution-phase methods. In addition to this advantageous method, the effects of two different polymers, one of which is better able to adhere to the crystal surface on which it is formed than the other, on the optoelectronic properties have been studied. Then, their current-voltage (I-V) and capacitance/conductance-voltage (C/(G/ω)-V) characteristics were investigated both in the dark and under illumination. The basic electrical parameters and the illumination-induced profile of the surface state (Nss) were probed by I-V and C-V measurements for two samples. A decrease in the barrier height (BH) and, consequently, a significant increase in the photocurrent were observed under illumination. Striking changes in series resistance (Rs) values are also highlighted. The photocapacitance and conductance characteristics indicated that the structures could be considered not only as photodiodes but also as photocapacitors. Moreover, the voltage-dependent changes of some photodetector parameters, such as responsivity (R), sensitivity (S), and specific detectivity (D*), along with the transient photocurrent characteristics, are discussed for both structures. Therefore, we can say that the strong changes in these parameters, which figure the merit of photodiode and photodetector applications, depending on the voltage and under illumination, prove that it is a study carried out in accordance with the purpose and so they can be used in electronic and optoelectronic applications.
