Si ve SiNW alttaşların metal oksit ince filmlerle kaplanması ve kızılötesi bölgede davranışının incelenmesi
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Date
2023-12-19
Authors
Bozdoğan, Ecem
Journal Title
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Publisher
Bursa Uludağ Üniversitesi
Abstract
Bu tez çalışmasında, dikey olarak hizalanmış farklı uzunluk ve çaplara sahip n tipi silisyum (Si) nanoteller (n-SiNWs), metal destekli kimyasal aşındırma yöntemi (MACE) kullanılarak <100> yönelimli ticari n-Si levhadan üretildi. Üretilen nanotel yapıların yapısal, elementel ve optiksel özellikleri araştırıldı. Daha sonra, üretilen n-SiNWs üzerine p tipi bakır I oksit filmler (Cu₂O)/n-SiNWs biçiminde heteroyapıları sentezlemek için elektrodepozisyon yöntemi kullanıldı. Ayrıca, p-Cu₂O ince filmler, termal buharlaştırma yöntemi (PVD) ile elde edilen Au/Cr/Si alttabakalar üzerine aynı depozisyon şartları altında büyütüldüler. İnce filmlerin depozisyon süreçleri dönüşümlü voltmetre tekniği ve akım-zaman grafikleri ile incelendi. X ışınları kırınımı (XRD) tekniği ile p-Cu₂O/n-SiNWs hetero ve Cu₂O/Au/Cr/Si yapıların kristolografik özellikleri araştırıldı. Bütün numunelerin tek fazlı kübik yapıya sahip oldukları gözlendi. Ek olarak, enine kesit alan emisyonlu aramalı elektron mikroskobu (FE-SEM)-enerji dağılımlı x-ışını spektroskopisi (EDX) karakterizasyonu ile p-Cu₂O/n-SiNWs hetero ve Cu₂O/Au/Cr/Si yapıların morfololjik özellikleri araştırıldı ve elementel analizleri yapıldı. Öte yandan, p-Cu₂O/n-SiNWs hetero ve Cu₂O/Au/Cr/Si yapıların yüzey pürüzlülükleri (Rq (nm)) ve tanecik boyutları atomik kuvvet mikroskobu (AFM) ile analiz edilerek hesaplandı. Değişen uzunluk/çap oranı ile birlikte Rq (nm) değerlerinin ve tanecik boyutlarının değiştiği görüldü. Yakın kızılötesi (UV-VIS-NIR) ve kızıl ötesi (FTIR) spektrometresi ile n-Si levha, nanotel yapıların ve p-Cu₂O/n-SiNWs heteroyapıların NIR ve IR bölgedeki optik özellikleri incelendi. Son olarak akım-gerilim (I-V) ölçümleri ile heteroyapıların diyot performansları belirlendi ve idealite faktörlerinin nanotellerin uzunluk/çap oranına bağlı olarak önemli ölçüde değiştiği bulundu.
In this thesis, the vertically aligned n-type silicon (Si) nanowires (n-SiNWs) with different lengths and diameters were fabricated from commercial n-Si wafers having <100> orientation by using metal-assisted chemical etching method (MACE). The structural, elemental and optical properties of the produced nanowire structures were investigated. Then, in order to obtain p-Cu₂O/n-SiNWs heterostructures, p type copper I oxide (Cu₂O) thin films were deposited on the produced n-SiNWs by the electrodeposition method. Furthermore, p-Cu₂O thin films were deposited on the surface of Au/Cr/Si substrates prepared by thermal evaporation method (PVD) under the same deposition conditions. The deposition processes of the thin films were examined by monitoring the cyclic voltmeter technique and current-time transients. The crystallographic properties of p-Cu₂O/n-SiNWs hetero and Cu₂O/Au/Cr/Si structures were investigated by the X-ray diffraction (XRD) technique, It was observed that they have a single-phase cubic structure. Furthermore, the morphological and elemental properties of p-Cu₂O/n-SiNWs hetero and Cu₂O/Au/Cr/Si structures were performed by cross-sectional field emission scanning electron microscopy-energy dispersive x-ray (FE-SEM EDX) characterization. On the other hand, surface roughness (Rq (nm)) and particle sizes of p-Cu₂O/n-SiNWs hetero and Cu₂O/Au/Cr/Si structures were calculated by atomic force microscopy (AFM). It was observed that Rq (nm) values and particle sizes changed with the changing aspect ratio. Near infrared (UV-VIS-NIR) and infrared region (FTIR) spectrometry showed that the reflectance values of nanowire structures and p-Cu₂O/n-SiNWs heterostructures were much lower than that of n-Si wafer. In addition, diode performances of heterostructures were determined by current-voltage (I-V) measurements and it was found that ideality factors changed significantly depending on the structure of nanowires.
In this thesis, the vertically aligned n-type silicon (Si) nanowires (n-SiNWs) with different lengths and diameters were fabricated from commercial n-Si wafers having <100> orientation by using metal-assisted chemical etching method (MACE). The structural, elemental and optical properties of the produced nanowire structures were investigated. Then, in order to obtain p-Cu₂O/n-SiNWs heterostructures, p type copper I oxide (Cu₂O) thin films were deposited on the produced n-SiNWs by the electrodeposition method. Furthermore, p-Cu₂O thin films were deposited on the surface of Au/Cr/Si substrates prepared by thermal evaporation method (PVD) under the same deposition conditions. The deposition processes of the thin films were examined by monitoring the cyclic voltmeter technique and current-time transients. The crystallographic properties of p-Cu₂O/n-SiNWs hetero and Cu₂O/Au/Cr/Si structures were investigated by the X-ray diffraction (XRD) technique, It was observed that they have a single-phase cubic structure. Furthermore, the morphological and elemental properties of p-Cu₂O/n-SiNWs hetero and Cu₂O/Au/Cr/Si structures were performed by cross-sectional field emission scanning electron microscopy-energy dispersive x-ray (FE-SEM EDX) characterization. On the other hand, surface roughness (Rq (nm)) and particle sizes of p-Cu₂O/n-SiNWs hetero and Cu₂O/Au/Cr/Si structures were calculated by atomic force microscopy (AFM). It was observed that Rq (nm) values and particle sizes changed with the changing aspect ratio. Near infrared (UV-VIS-NIR) and infrared region (FTIR) spectrometry showed that the reflectance values of nanowire structures and p-Cu₂O/n-SiNWs heterostructures were much lower than that of n-Si wafer. In addition, diode performances of heterostructures were determined by current-voltage (I-V) measurements and it was found that ideality factors changed significantly depending on the structure of nanowires.
Description
Keywords
Silisyum nanotel, MACE, Bakır I oksit, Elektrodepozisyon, Yapısal ve optiksel karakterizasyon, Silicon nanowire, Metal oxide, Electrodeposition, Structural and optical analysis
Citation
Bozdoğan, E. (2023). Si ve SiNW alttaşların metal oksit ince filmlerle kaplanması ve kızılötesi bölgede davranışının incelenmesi. Yayınlanmamış doktora tezi. Bursa Uludağ Üniversitesi Fen Bilimleri Enstitüsü.