We investigated the electronic structure of Mg-, Si-, and Zn-doped four-faceted [001]- and [110]-oriented SnO₂ nanowires using first-principles calculations based on the linear combination of atomic orbitals (LCAO) method. This approach, employing atomic-centered Gaussian-type functions as a basis set, was combined with hybrid density functional theory (DFT). Our results show qualitative agreement in predicting the formation of stable point defects due to atom substitutions on the surface of the SnO₂ nanowire. Doping induces substantial atomic relaxation in the nanowires, changes in the covalency of the dopant–oxygen bond, and additional charge redistribution between the dopant and nanowire. Furthermore, our calculations reveal a narrowing of the band gap resulting from the emergence of midgap states induced by the incorporated defects. This study provides insights into the altered electronic properties caused by Mg, Si, and Zn doping, contributing to the further design of SnO₂ nanowires for advanced electronic, optoelectronic, photovoltaic, and photocatalytic applications.

Electrochemical deposition into a prepared SiO₂/Si-p ion track template was used to make orthorhombic SnO₂ vertical nanowires (NWs) for this study. As a result, a SnO₂-NWs/SiO₂/Si nanoheterostructure with an orthorhombic crystal structure of SnO₂ nanowires was obtained. Photoluminescence excited by light with a wavelength of 240 nm has a low intensity, arising mainly due to defects such as oxygen vacancies and interstitial tin or tin with damaged bonds. The current–voltage characteristic measurement showed that the SnO₂-NWs/SiO₂/Si nanoheterostructure made this way has many p-n junctions.

In this study, chemical deposition was used to synthesize structures of Ga₂O₃ -NW/SiO₂/Si (NW—nanowire) at 348 K and SnO₂-NW/SiO₂/Si at 323 K in track templates SiO₂/Si (either n- or p-type). The resulting crystalline nanowires were δ-Ga₂O₃ and orthorhombic SnO₂. Computer modeling of the delta phase of gallium oxide yielded a lattice parameter of a = 9.287 Å, which closely matched the experimental range of 9.83–10.03 Å. The bandgap is indirect with an Eg = 5.5 eV. The photoluminescence spectra of both nanostructures exhibited a complex band when excited by light with λ = 5.16 eV, dominated by luminescence from vacancy-type defects. The current–voltage characteristics of δ-Ga₂O₃ NW/SiO₂/Si-p showed one-way conductivity. This structure could be advantageous in devices where a reverse current is undesirable. The p-n junction with a complex structure was formed. This junction consists of a polycrystalline nanowire base exhibiting n-type conductivity and a monocrystalline Si substrate with p-type conductivity. The I–V characteristics of SnO₂-NW/SiO₂/Si suggested near-metallic conductivity due to the presence of metallic tin.

В данной работе проведен синтез орторомбических нанопроволок (НП) SnO₂ методом электрохимического осаждения в подготовленный ионно-трековый темплэйт SiO₂/Si-p. Трекообразования в структуре SiO₂/Si создавались путем облучения на циклотроне ДЦ-60 быстрыми тяжелыми ионами Xe с энергией 200 МэВ (Ф = 10⁸ см⁻²). Для формирования нанопористых шаблонов использовали 4% водный раствор фтористоводородной кислоты (HF). Электрохимическое осаждение (ЭХО) SnO₂ в трековый темплэйт осуществляли при комнатной температуре, напряжение на электродах составляла 1,75 В. При процессе ЭХО, был использован электролит со следующим химическим составом: 6 г/л SnCl₂ (Sigma-Aldrich) – 25 мл H₂O – 2 мл HCl («хч»; 35%; ρ = 1,1740 г/см³). Морфология поверхности образцов, после процесса ЭХО, исследовались на двухлучевом сканирующем микроскопе Zeiss Crossbeam 540. Фазовый состав, кристаллографическая структура наногетероструктур (SnO₂/SiO₂/Si) с заполнением нанопор диоксидом олова исследовали с помощью рентгеновской дифракции (XRD) на многофункциональном рентгеновском дифрактометре Rigaku SmartLab. Фотолюминесценция измерялась в оптическом диапазоне 320–600 нм с использованием спектрофлуориметра СМ2203 (Solar). Исследование электрических характеристик синтезированных нанопроволок диоксида олова проводилось с использованием патенциостата VersaStat 3 фирмы Ametek. В результате была получена наногетероструктура SnO₂-НП/SiO₂/Si с орторомбической кристаллической структурой нанопроволок SnO₂. Фотолюминесценция, возбуждаемая светом с длиной волны 240 нм, имеет низкую интенсивность, возникающую в основном за счет таких дефектов, как кислородные вакансии и междоузельное олово или олово поврежденными связями. Измерение ВАХ показало, что полученная таким образом наногетероструктура SnO₂-НП/SiO₂/Si содержит массивы p-n переходов.

Metal-coated mesoporous PSi (mesoPSi) opens up disruptive perspectives for biosensing, which is primarily enabled by surface-enhanced Raman scattering (SERS). Although the unique performance of SERS-active substrates based on metal-coated mesoPSi has already been praised, influence of defects in silicon wafer on its morphology has not been revealed. Defects lead to formation of spiral regions in mesoPSi with varying porosity, which affects SERS activity of the overlying metallic nanostructures. It limits the reliability of SERS analysis. Here, we investigate repeatability of morphology and SERS activity of silver particles on mesoPSi as a function of defects in parent silicon, which are induced by irregular dopant levels. We propose an original corrosion approach that has not yet been applied to control the morphology of silicon nanostructures in general and mesoPSi in particular. By replacing silicon nanocrystallites with sacrificial copper nanoparticles, we were able to eliminate the surface irreproducibility of mesoPSi. The copper-corrosion-modified porous silicon surface was shown to be a suitable substrate for reliable SERS-active substrates. In more detail, SERS-active substrate based on mesoPSi without a defective surface layer allowed for a more than 40% increase in the SERS-active surface area with a signal deviation of only 10 % compared to that with a defective layer.

This work presents a study of the structural, optical and electrical characteristics of tin dioxide (SnO2) nanowires obtained by chemical deposition (CD) into a SiO₂/Si track template (template synthesis). Latent tracks in the SiO₂ layer were created by irradiation with swift heavy ions (SHI) of Xe at an energy of 200 MeV with a fluence of Ф = 10⁸ cm⁻² and subsequent etching in a 4% aqueous solution of hydrofluoric acid (HF). The chosen CD method is widely used for the deposition of semiconductor oxide nanowires in SiO₂ nanopores. The CD method is cost-effective because it does not require special equipment for deposition of nanowires. To carry out deposition, a solution of a coordination compound of a metal and a reducing agent is used. To analyze the filling of pores after the CD process, the surface morphology of the samples was studied using a Zeiss Crossbeam 540 scanning microscope. The crystallographic structure of SnO₂/SiO₂/Si nanostructures with SnO₂ nanopore filling was studied by X-ray diffraction. X-ray diffraction analysis (XRD) is carried out on a Rigaku SmartLab X-ray diffractometer. As a result, a SnO₂-NW/SiO₂/Si nanoheterostructure with an orthorhombic crystal structure of SnO₂ nanowires was obtained. Photoluminescence (PL) spectra were measured upon excitation with light at a wavelength of 240 nm using a CM2203 spectrofluorimeter (Solar). Gaussian decomposition of the photoluminescence spectrum of SnO₂-NW/SiO₂/Si structures showed that they have low intensity, which is mainly due to the presence of defects such as oxygen vacancies, interstitial tin or tin with damaged bonds. Electrical characterization studies were performed using a VersaStat 3 potentiostat (Ametek). Measurement of the current-voltage characteristic showed that the resulting SnO₂-NW/SiO₂/Si nanoheterostructure contains arrays of p-n junctions.