Mun Jeong Choi, Dong Ho Lee, Han Seul Kim, Geon Hwee Kim
Silicon nano/microstructures have attracted significant interest for their applications in electronics, sensors, and energy devices. However, conventional photolithography-based fabrication processes face challenges such as high cost, procedural complexity, and limited scalability for large-area patterning. In this study, we propose a novel and cost-effective fabrication method to precisely create silicon nano/microstructures by utilizing metal mask patterning based on electrospinning. The palladium (Pd) nanocluster patterns, with linewidths below 1 µm formed by electrospinning, act either as catalysts or protective masks depending on the etching environment. Under acidic conditions, Pd acts as a catalyst for metal-assisted chemical etching (MACE), forming semicircular silicon structures along the nanofiber patterns. In alkaline environments, the porous nature of the Pd clusters allow partial penetration of the etchant, enabling anisotropic etching and lift-off effects that produce pyramid-shaped microgrooves with crystallographic angles of 54.74°. This process achieves structures with 5–10 µm linewidths and feature spacing as narrow as 1 µm. Conducted under atmospheric pressure and without the need for expensive equipment, this technique presents strong potential for next-generation microelectronic and biosensing applications.
{"title":"High-Precision Silicon Microgrooves via Metal-Assisted Chemical Etching (MACE) Using Electrospun Nanofibers","authors":"Mun Jeong Choi, Dong Ho Lee, Han Seul Kim, Geon Hwee Kim","doi":"10.1002/admi.202500578","DOIUrl":"https://doi.org/10.1002/admi.202500578","url":null,"abstract":"<p>Silicon nano/microstructures have attracted significant interest for their applications in electronics, sensors, and energy devices. However, conventional photolithography-based fabrication processes face challenges such as high cost, procedural complexity, and limited scalability for large-area patterning. In this study, we propose a novel and cost-effective fabrication method to precisely create silicon nano/microstructures by utilizing metal mask patterning based on electrospinning. The palladium (Pd) nanocluster patterns, with linewidths below 1 µm formed by electrospinning, act either as catalysts or protective masks depending on the etching environment. Under acidic conditions, Pd acts as a catalyst for metal-assisted chemical etching (MACE), forming semicircular silicon structures along the nanofiber patterns. In alkaline environments, the porous nature of the Pd clusters allow partial penetration of the etchant, enabling anisotropic etching and lift-off effects that produce pyramid-shaped microgrooves with crystallographic angles of 54.74°. This process achieves structures with 5–10 µm linewidths and feature spacing as narrow as 1 µm. Conducted under atmospheric pressure and without the need for expensive equipment, this technique presents strong potential for next-generation microelectronic and biosensing applications.</p>","PeriodicalId":115,"journal":{"name":"Advanced Materials Interfaces","volume":"13 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://advanced.onlinelibrary.wiley.com/doi/epdf/10.1002/admi.202500578","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145930991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wiktoria Lipińska, Emerson Coy, Katarzyna Grochowska, Justyna Gumieniak, Agnieszka Kramek, Ryan W. Crisp, Stefania Wolff, Katarzyna Siuzdak
Transition metal sulfides have been widely investigated as electrocatalysts for both the oxygen and hydrogen evolution reactions. Here, we synthesized copper, nickel, cobalt, and iron sulfides using a facile successive ionic layer adsorption reaction (SILAR) occurring in porous transparent titanium dioxide nanotubes. Nanotubes are fabricated by anodization of a titanium layer sputtered onto indium tin oxide-coated glass slides. X-ray photoelectron spectroscopy measurements confirmed the presence of copper oxides and sulfides, cobalt oxides and sulfides, nickel oxides and sulfides as well as iron oxides. Although the walls of the titania nanotubes are modified using 5 mm aqueous solutions containing the metal and sulfide ions, the initial transparency has been preserved. According to microscopic studies and elemental analysis, the sulfides are uniformly distributed on the walls forming a metal oxide/metal sulfide heterojunction. Among all investigated materials, titania overgrown by cobalt oxide and sulfide exhibits the highest current density of 28 mA cm−2 recorded at +2.1 V vs. RHE during oxygen evolution, while the non-modified electrode reached only 1.5 mA cm−2. Taking into account both the high transparency and activity toward oxygen evolution, the investigated electrodes are an important element for a semitransparent tandem device for overall water splitting.
过渡金属硫化物作为析氧和析氢反应的电催化剂已被广泛研究。在这里,我们利用发生在多孔透明二氧化钛纳米管中的简单连续离子层吸附反应(SILAR)合成了铜、镍、钴和铁的硫化物。纳米管是通过阳极氧化将钛层溅射到氧化铟锡镀膜玻片上制备的。x射线光电子能谱测量证实了铜氧化物和硫化物、钴氧化物和硫化物、镍氧化物和硫化物以及铁氧化物的存在。尽管使用含有金属和硫化物离子的5毫米水溶液对二氧化钛纳米管的壁进行了修饰,但仍保留了最初的透明度。微观研究和元素分析表明,硫化物均匀分布在壁上,形成金属氧化物/金属硫化物异质结。在所有被研究的材料中,氧化钴和硫化物覆盖的二氧化钛在+2.1 V相对于RHE的析氧过程中显示出最高的电流密度为28 mA cm−2,而未修饰的电极仅达到1.5 mA cm−2。考虑到高透明度和析氧活性,所研究的电极是用于整体水分解的半透明串联装置的重要元件。
{"title":"Transparent Electrodes Composed of Organized Titania Nanotubes and Transition Metal Sulfides for the Oxygen Evolution Reaction","authors":"Wiktoria Lipińska, Emerson Coy, Katarzyna Grochowska, Justyna Gumieniak, Agnieszka Kramek, Ryan W. Crisp, Stefania Wolff, Katarzyna Siuzdak","doi":"10.1002/admi.202500606","DOIUrl":"https://doi.org/10.1002/admi.202500606","url":null,"abstract":"<p>Transition metal sulfides have been widely investigated as electrocatalysts for both the oxygen and hydrogen evolution reactions. Here, we synthesized copper, nickel, cobalt, and iron sulfides using a facile successive ionic layer adsorption reaction (SILAR) occurring in porous transparent titanium dioxide nanotubes. Nanotubes are fabricated by anodization of a titanium layer sputtered onto indium tin oxide-coated glass slides. X-ray photoelectron spectroscopy measurements confirmed the presence of copper oxides and sulfides, cobalt oxides and sulfides, nickel oxides and sulfides as well as iron oxides. Although the walls of the titania nanotubes are modified using 5 m<span>m</span> aqueous solutions containing the metal and sulfide ions, the initial transparency has been preserved. According to microscopic studies and elemental analysis, the sulfides are uniformly distributed on the walls forming a metal oxide/metal sulfide heterojunction. Among all investigated materials, titania overgrown by cobalt oxide and sulfide exhibits the highest current density of 28 mA cm<sup>−2</sup> recorded at +2.1 V vs. RHE during oxygen evolution, while the non-modified electrode reached only 1.5 mA cm<sup>−2</sup>. Taking into account both the high transparency and activity toward oxygen evolution, the investigated electrodes are an important element for a semitransparent tandem device for overall water splitting.</p>","PeriodicalId":115,"journal":{"name":"Advanced Materials Interfaces","volume":"13 2","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://advanced.onlinelibrary.wiley.com/doi/epdf/10.1002/admi.202500606","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146007522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Junyoung Park, Nayeon Kim, Jung-Eun Choi, Yujin Yeo, Min-Seok Kim, Beom-Jun Seo, Chin-Wook Chung
The fabrication of next-generation semiconductor and quantum devices with complex 3D architectures requires etching processes that enable highly anisotropic profiles while minimizing plasma-induced damage. However, conventional plasma processes face fundamental limitations, including plasma-induced damage and limited control over etch anisotropy. In particular, fluorine-rich plasmas such as CF4 inherently struggle to achieve vertical profiles due to insufficient sidewall passivation. This study demonstrates that vertical etch profiles can be achieved under ultra-low electron temperature (ULET) conditions in fluorine-rich Ar/CF4 plasma. Under conventional high electron temperature (Te) conditions without radio-frequency (rf) bias power, Ar/CF4 plasma produces isotropic profiles characterized by undercut and a rounded trench bottom. When Te is reduced to ≈ 0.5 eV, the profile transitions from isotropic to anisotropic, resulting in suppressed undercut and a flattened trench bottom. This transition is attributed to enhanced sidewall passivation, driven by an increased CFx/F ratio at low-Te conditions. Moreover, applying moderate rf bias (7 W) to the ULET plasma improves the vertical etch rate and anisotropy without distortion. However, excessive bias power (>18 W) leads to electron heating, which reintroduces distortion. These findings establish Te as a decisive parameter and demonstrate that ULET plasma enables highly anisotropic etching with minimized distortion in fluorine-rich chemistries.
{"title":"Realizing Vertical Etch Profiles in Fluorine-Rich Ar/CF4 Plasma","authors":"Junyoung Park, Nayeon Kim, Jung-Eun Choi, Yujin Yeo, Min-Seok Kim, Beom-Jun Seo, Chin-Wook Chung","doi":"10.1002/admi.202500940","DOIUrl":"https://doi.org/10.1002/admi.202500940","url":null,"abstract":"<p>The fabrication of next-generation semiconductor and quantum devices with complex 3D architectures requires etching processes that enable highly anisotropic profiles while minimizing plasma-induced damage. However, conventional plasma processes face fundamental limitations, including plasma-induced damage and limited control over etch anisotropy. In particular, fluorine-rich plasmas such as CF<sub>4</sub> inherently struggle to achieve vertical profiles due to insufficient sidewall passivation. This study demonstrates that vertical etch profiles can be achieved under ultra-low electron temperature (ULET) conditions in fluorine-rich Ar/CF<sub>4</sub> plasma. Under conventional high electron temperature (<i>T</i><sub>e</sub>) conditions without radio-frequency (rf) bias power, Ar/CF<sub>4</sub> plasma produces isotropic profiles characterized by undercut and a rounded trench bottom. When <i>T</i><sub>e</sub> is reduced to ≈ 0.5 eV, the profile transitions from isotropic to anisotropic, resulting in suppressed undercut and a flattened trench bottom. This transition is attributed to enhanced sidewall passivation, driven by an increased CF<sub>x</sub>/F ratio at low-<i>T</i><sub>e</sub> conditions. Moreover, applying moderate rf bias (7 W) to the ULET plasma improves the vertical etch rate and anisotropy without distortion. However, excessive bias power (>18 W) leads to electron heating, which reintroduces distortion. These findings establish<i> T</i><sub>e</sub> as a decisive parameter and demonstrate that ULET plasma enables highly anisotropic etching with minimized distortion in fluorine-rich chemistries.</p>","PeriodicalId":115,"journal":{"name":"Advanced Materials Interfaces","volume":"13 1","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://advanced.onlinelibrary.wiley.com/doi/epdf/10.1002/admi.202500940","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145930834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carbon-doped TiO2 nanoparticles were prepared by a facile carbothermal treatment at different temperatures. The synthesis was conducted in a rotary tube furnace under an acetylene/nitrogen gas flow. A detailed analysis of the morphology of the particles revealed a layered graphene structure surrounding the TiO2 core with a temperature-dependent shell thickness of 1–1.5 nm. The material exhibits a significant shift in the Raman Eg(1) mode toward higher wavenumbers. High carbon contents were determined by X-ray photoelectron spectroscopy. This led to the conclusion that in addition to the carbon in the shell, carbon is also incorporated into the TiO2 structure. Substitutional doping in favor of titanium or oxygen atoms could be excluded based on XPS measurements due to the absence of Ti–C bonds and the lack of changes in lattice parameters of the unit cell or microstrain. An interstitial incorporation of carbon is therefore most likely. Either the incorporation of carbon or the carbon shell suppressed the phase transition from anatase to the thermodynamically stable rutile which is expected above 600