Saf ZnO ve katkılı ZnO:Al:Mnx (x=1%, 2%, 3%, 5% at.) yarı iletken ince filmlerin yapısal ve optiksel özellikleri ile üretilen diyotların elektriksel özelliklerinin araştırılması

In this work, undoped and co-doped ZnO:Al:Mn semiconductor thin films and p-type Si diodes were produced via sol-gel technique method. The morphological and optical properties of the produced thin films were investigated using SEM, XRD and UV-Spectrophotometer, respectively. It was observed that the crystal structure of the semiconductor samples had a hexagonal wurtzite structure and the forbidden energy gaps of the samples decreased with increasing Mn contribution. The experimental zero-feed current barrier height (?b(I-V)), rectification ratio, ideality factor and Ion/Ioff parameters of the diodes were determined via the thermionic emission model. It was determined that the produced Al/p-Si/ZnO:Al:Mn/Al diode had high rectification ratio and Ion/Ioff values of 1.56x105 and 1.54x104, respectively, and exhibited light-sensitive behaviour. Also, the capacitance barrier height (?b(C-V)), built-in voltage (Vbi), diffusion potential (Vd), donor concentration (Nd) and depletion layer width (Wd) values of Al/p-Si/ZnO:Al:Mn/Al diode were calculated via the C-2-V graph drawn under 1MHz frequency. The results show that the fabricated diodes can be used as photodiodes or photosensors in optoelectronic applications. © 2023 Gazi Universitesi Muhendislik-Mimarlik. All rights reserved.Firat Üniversitesi, FU: FF16.24This study was supported by Firat University, for PhD thesis (Project No. FF16.24)

Controlling of crystal size and optical band gap of CdO nanopowder semiconductors by low and high Fe contents

The CdO:Fe nanopowder semiconductors were synthesized by the sol–gel calcination for the first time. The structural properties of Fe doped CdO samples were analyzed by AFM and XRD measurements. XRD patterns of the pure and Fe-doped CdO samples reveal that the pure and Fe doped CdO nanopowders are polycrystalline of cubic CdO structure. The crystallite size of undoped and Fe-doped CdO samples is changed unsystematically with a regular increase of Fe content. The optical band gaps of Fe doped CdO samples were determined for the first time by diffused reflectance measurements. The optical band gap of the samples is increased with the increase of Fe dopant inside the host matrix (CdO) up to 15 % followed by a decrease in its value. It is evaluated that Fe doped CdO nanopowder semiconductors can be producted by sol–gel calcination for advanced technological application

Design and fabrication of dioxyphenylcoumarin substituted cyclotriphosphazene compounds photodiodes

The present study introduces cyclotriphosphazene compounds substituted by dioxyphenylcoumarin as a photodiode application. Firstly, 7,8-dihydroxy-3-(3-methylphenyl)coumarin (1b) has been obtained by conventional as well as microwave assisted methods. Novel optoelectronic device characteristics for both mono and disubstituted dioxyphenylcoumarin bearing cyclotriphosphazene compounds (HCP-2 and HCP-4) have been synthesized from the reactions of cyclotriphosphazene containing dioxybiphenyl (HCP-1 and HCP-3) with compound 1b, respectively. The structures of compounds HCP 1–4 were identified by using elemental analysis, 1H, 13C-APT, 31P NMR and 2D HETCOR NMR and FT-IR spectroscopy methods. The Al/HCP-2/p-Si/Al and Al/HCP-4/-p-Si/Al photodiodes properties have been investigated from current-voltage (I−V) and capacitance-voltage (C−V) measurements. The electrical parameters of the prepared diodes such as ideality factor n and series resistance Rs were investigated in dark and at room temperature from (I−V) curve and Nord's method. As can be seen, the Al/HCP-2/p-Si/Al diode of high rectification ratio RR and with ideality factor greater than unity. The influence of light illuminations on the diode shows that the device can be used as photodiode with good efficiency. The barrier height ϕb and series resistance Rs have been calculated from the capacitance-voltage (C−V)and conductance-voltage (G−V) measurements under various applied frequencies from 10 kHz to 1 MHz. the high difference in the results of barrier height obtained from I-V and C-V calculations confirm the influence of series resistance and localized states on transport of charge carriers and the photodiode performance.TUBITAK-110T652 Fırat University, FÜBAP-FF.161