Ömer Sevgili

Al/NiO/p-Si Schottky diyot (SD) üretimi bir termal buharlaştırma sistemi kullanılarak oluşturulmuştur. Bir arayüzey tabakası olarak kullanılan NiO’in yapısal analizi Taramalı Elektron Mikroskobu (SEM) kullanılarak gerçekleştirilmiş ve SEM yan kesit görüntüsünden NiO arayüzey tabakasının kalınlığı 0,0345 µm olarak bulunmuştur. Al/NiO/p-Si SD’nin elektriksel özelliklerini frekansa bağlı karakterize etmek amacıyla C-V ve G/-V ölçümleri 50-5000 kHz frekans aralığında ve -3 V ile +3 V aralığında gerçekleştirilmiştir. Seri direnci (Rs) hesaplamak için Nicollian-Brews yöntemi kullanılırken, arayüzey durumlarını (Nss) hesaplamak için yüksek-düşük frekans kapasitans yöntemi (CHF-CLF) kullanılmıştır. Nss değerinin 1012 eV-1cm-2 mertebesinde olduğu belirlenmiştir. Bu bulgular, NiO'nun elektronik cihazlardaki geleneksel yalıtkan katmanlara umut verici bir alternatif olduğunu göstermektedir.

This study evaluates the effect of the Mg ₃ N ₂ interlayer on interface characteristics by investigating the electrical, impedance, and dielectric properties of Ag/Mg ₃ N ₂ /p-Si Schottky diodes. The study specifically aims to reveal the interface trap density ( N _ss ), series resistance ( R _s ), and frequency-dependent behavior of the dielectric response. The Mg ₃ N ₂ thin film was deposited on a p-type Si substrate using the thermal evaporation method. Electrical characterizations were performed at room temperature and in the dark; capacitance ( C - V ) and conductance ( G/ω - V ) measurements were taken in the 10 kHz–5 MHz frequency range. The N _ss was calculated using the Hill-Coleman method, while the complex dielectric constant ( ε′ , ε″ ), loss factor ( tanδ ), electrical modulus ( M′ , M″ ), and AC conductivity ( σ _AC ) were calculated using standard formulations. The ε ′, ε ″, tan δ , M′ , M″ , and σ _AC values were determined to be 6.91, 7.43, 1.07, 0.06, 0.07 and 4.13 × 10 ^-6 Ω ^-1 .cm ^-1 at high frequency (1 MHz) and high voltage (+ 3 V), while the N _ss value was on the order of 10 ¹³ eV ^-1 ·cm ^-2 . The study provides important insights into understanding the impact of the Mg ₃ N ₂ interlayer on SD performance and highlights the potential contributions of such interlayer engineering in electronic device designs.

This study presents rhodamine hybrids comprising para-quinonemethide groups (Rh-PQMs). Rh-PQMs ( MI and MII ) exist in open and closed ring conformations and present promising possibilities as semiconductors due to the differences in their absorptions and fluorescence. In this regard, we explored the electrical character of photo diodes (PDs), including Rh-PQMs (MI-closed/open and MII-closed/open) as the interfacial layers. These PDs were characterized in the dark and under illumination of different intensities. Surprisingly, only the MI-open and MII-open showed favorable outcomes. MII-open PD had a five-fold increased rectifier ratio compared to MI-open PD at ±2 V voltage. In the presence of 100 mW cm ⁻² illumination at −2 V, the MI-open PD recorded a current of about 100 µ A, whereas the MII-open PD recorded a current of about 80 µ A. Additionally, the work examined spectral sensitivity, detectivity, noise equivalent power, and external quantum efficiency of both PDs. Experiments showed the prospect of Rh-PQMs′ open conformations as viable devices with tolerable performances.

HgS nanomaterials were synthesized using an ultrasound-assisted method, and their optical and morphological properties were analyzed through UV–Vis spectroscopy and scanning electron microscopy (SEM). The capacitance–voltage (C–V) and conductance–voltage (G/ω–V) measurements of the Au/(HgS-PVA)/n-Si (MPS) capacitor were conducted across a frequency range of 1 kHz–5 MHz. The experimental data were used to investigate the effects of surface states (N _ss) and series resistance (R _s). Both C and G/ω increased at lower frequencies, as the surface states could follow the AC signal, contributing to the overall response. The density of N _ss was derived using the high-low frequency (HF) capacitance method and parallel conductance technique, while Nicollian–Brews’ method was employed to extract the R _s. This study reveals that the conductance method yields higher values than the HF C–V method, attributed to its sensitivity to fast interface states and distributed trap time constants. The observed frequency-dependent losses in G _p/ω measurements confirm the presence of a continuous trap distribution near the HgS-PVA/n-Si surface, significantly influencing device reliability. The average N _ss was calculated to be ~ 10¹² eV⁻¹ cm⁻², indicating a well-controlled interface. The obtained N _ss and R _s values suggest that the HgS-PVA nanocomposite is a promising alternative to conventional insulating layers (e.g., SiO₂ or SnO₂) in electronic devices, thanks to its favorable electrical properties.

This study presents a structural analysis of NiO and the fabrication of Al/NiO/p-Si isotype heterojunction photodiode (PD) as well as an investigation of the photo-response and photovoltaic (PV) properties of the PD in the various illumination intensities. The series resistance (R _S ) value of the Al/NiO/p-Si was calculated to be 0.11 kΩ using Ohm’s Law at 2 V. This result corroborates the assertion that R_S is the pivotal parameter for attaining optimal performance in a PD. The NiO has made a notable improvement to the electrical parameters such as ideality factor, barrier height, and series resistance. The spectral responsivity R value of the PD was calculated as 1.59 A W⁻¹ at −2 V. The Al/NiO/p-Si exhibited a short-circuit current density (J _SC ) of 60.38 mA·cm⁻², an open-circuit voltage (V _OC ) of 149.0 mV, a fill factor (FF) of 27.67%, and a power conversion efficiency (PCE) of 2.49%. In view of the experimental results, it can be concluded that NiO represents a promising material for the optimization of heterojunction photodiode applications.

The synthesis and investigation of photoelectric studies of simple organic compounds as organic interlayers are of significant importance and widely studied. As such, we synthesized naphthalene diimide (NDI)-appended ruthenium complexes (Ru-NDIs) to function as the interface layer, and have fabricated novel Al/NDIs or Ru-NDIs/p-Si devices (D1-D4) to investigate their photoelectric properties. Subsequently, we compared and discussed the photoelectric properties of these devices after synthesis and fabrication. According to this, the band-gap energy (E _g ) values of organic materials were found to range from 2.95 eV to 3.14 eV, making them ideal for solar cells applications. Additionally, the photoresponse (Pr) values of Al/NDIs or Ru-NDIs/p-Si devices (D1-D4) were found to be 59.25, 1593.08, 198.77, and 134.47, respectively. Moreover, the Al/Ru-NDIs/p-Si D2 structure exhibited the highest Pr values. Experimental results indicate that since the four optoelectronic devices arranged with the derivation of synthesized compounds have good photoresponse characteristics, they can be utilized as a photosensor or photodiodes in different electronic and optoelectronic technologies.

The Ag/Mg₃N₂/p-Si heterojunction diode (HD) with rectifier contacts (RCs) with the same area in various geometries were fabricated through thermal evaporation, and the electrical performances of these diodes was compared. The geometry of the RC was found to affect various electrical properties such as ideality factor, saturation current and barrier height of HD, the rectifier rate, and the leakage current of the diodes. The experimental demonstrated the HD with a circular RC exhibited a higher rectifying ratio and lower leakage current compared to the other RCs. Hence, the design and optimization of the RC play a critical role in achieving the desired electrical properties of diode. These diodes, featuring an Mg₃N₂ interfacial layer and showcasing photoconductive behavior, can be utilized as photodiodes in various optoelectronic devices.

This study presents the morphological, electrical, and photosensitive behavior properties of the Al/(NaYF ₄ :Yb,Er)/p-Si structure. The (NaYF ₄ :Yb,Er) used as an interfacial layer was deposited on a p-Si semiconductor using the thermal evaporation method. The surface morphological properties of the evaporated interfacial layer were examined using scanning electron microscopy and atomic force microscopy. The ideality factor of the structure increases from 3.58 at 320 K to 8.16 at 100 K with decreasing temperature, while the barrier height decreases from 0.80 eV at 320 K to 0.31 at 100 K with decreasing temperature in the same temperature range. The photosensitive behavior of the fabricated structure were investigated using UV-A lamp with 350 nm wavelength. The spectral responsivity, photosensitivity, and detectivity values for the Al/(NaYF ₄ :Yb,Er)/p-Si structure were found to be 0.525 A.W⁻¹, 2841.38, and 2.16 × 10¹¹ Jones, respectively.