Article
Chemistry, Multidisciplinary
Devon S. Jakob, Nengxu Li, Huanping Zhou, Xiaoji G. Xu
Summary: This article introduces a novel method to generate Coulombic force in KPFM, increasing the spatial resolution to approximately 25 nm. By integrating PiFM, high spatial resolution chemical distributions and surface potential maps can be obtained concurrently. This is expected to facilitate characterizations of nanoscale electrical properties of photoactive materials, semiconductors, and ferroelectric materials.
Article
Energy & Fuels
Christian Kameni Boumenou, Amala Elizabeth, Finn Babbe, Alice Debot, Harry Moeenig, Alex Redinger
Summary: The study investigated the buried MoSe2/CuInSe2 interface of stoichiometric absorbers in thin film solar cells, revealing differences in local density of states compared to the front-side properties. This sheds new light on the complex interface formation in CuInSe2-based thin film solar cells grown under Cu-rich conditions.
PROGRESS IN PHOTOVOLTAICS
(2021)
Article
Chemistry, Multidisciplinary
Mengkang Xu, Xinpeng Tian, Qian Deng, Qun Li, Shengping Shen
Summary: By introducing nanocracks and applying continuously varying mechanical loading, the evolution of flexoelectricity around the crack tips in SrTiO3, Ba0.67Sr0.33TiO3, and TiO2 samples has been successfully measured. This method provides a reliable way to identify the significance of the flexoelectric effect and may open a new avenue for the study of flexoelectricity involving multiple physics phenomena such as flexoelectronics and the flexo-photovoltaic effect.
Article
Chemistry, Multidisciplinary
Shangzhi Gu, Wenyu Liu, Shuo Mi, Guoyu Xian, Jiangfeng Guo, Fei Pang, Shanshan Chen, Haitao Yang, Hong-Jun Gao, Zhihai Cheng
Summary: In this study, the twist angle-dependent work functions of twisted bilayer graphene (tBLG) were investigated using Kelvin probe force microscopy (KPFM) and Raman spectroscopy. The surface potentials of Bernal-stacked multilayer graphene were measured to determine the relationship between twist angle and surface potential. It was found that the work function of tBLG decreases and tends to saturate with increasing number of layers. Controlled annealing process showed that tBLG transforms into Bernal-stacked bilayer graphene. This research provides valuable insights into the twist angle-dependent surface potentials and electronic properties of tBLG.
Article
Chemistry, Physical
Hwi Je Woo, Seongchan Kim, Young-Jin Choi, Jeong Ho Cho, Seong Heon Kim, Young Jae Song
Summary: The work function of graphene devices on SiO2 substrates is studied using Kelvin probe force microscopy, revealing gate voltage-dependent work-function hysteresis. The inhomogeneous distribution of chemical species at the graphene/SiO2 interface leads to varying degrees of hysteresis across different positions on the graphene.
Article
Nanoscience & Nanotechnology
Ryo Izumi, Masato Miyazaki, Yan Jun Li, Yasuhiro Sugawara
Summary: The recently proposed high-low Kelvin probe force microscopy (KPFM) allows for the evaluation of semiconductor interface states with high spatial resolution using high and low AC bias frequencies. This is important for assessing the energy spectrum of interface state density in semiconductor devices. In this study, a method called high-low Kelvin probe force spectroscopy (high-low KPFS) is proposed, which measures the interface state density inside semiconductors using high and low-frequency AC bias voltages. Preliminary experiments on ion-implanted silicon surfaces confirmed the dependence of electrostatic force on AC bias voltage frequency and obtained the interface state density.
BEILSTEIN JOURNAL OF NANOTECHNOLOGY
(2023)
Article
Physics, Applied
Tomoe Kuroiwa, Takuji Takahashi
Summary: This study introduces an intermittent bias application method and a pump-probe method into P-KFM to achieve time-resolved measurements for examining the photo-carrier dynamics in Cu(In,Ga)Se-2 solar cells. The research provides direct observation of rising and decay waveforms of photovoltage and two-dimensional observation of photovoltage distributions at different time intervals between optical pump and electrical probe pulses.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Jill Serron, Albert Minj, Valentina Spampinato, Alexis Franquet, Yevhenii Rybalchenko, Marie-Emmanuelle Boulon, Steven Brems, Henry Medina Silva, Yuanyuan Shi, Benjamin Groven, Renan Villarreal, Thierry Conard, Paul van der Heide, Thomas Hantschel
Summary: This study investigates the rapid intercalation of water vapor at the interface of transition metal dichalcogenides (TMDs) and sapphire, as well as between two TMD monolayers, and examines its impact on their electrical properties. The findings reveal that water vapor can intercalate rapidly within a few minutes and show partial reversibility under (ultra)-high vacuum conditions. Complete desorption of intercalated water clusters significantly enhances the electronic properties of TMDs, but also indicates that the characterization of TMD samples is significantly affected by the presence of water intercalation in air, inert environments, and even vacuum. Moreover, the study highlights a correlation between water intercalation and the presence of defects, contributing to the gradual degradation of TMDs as they age.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Woongbin Yim, Van Tu Nguyen, Quynh Thi Phung, Hwan Sik Kim, Yeong Hwan Ahn, Soonil Lee, Ji-Yong Park
Summary: The spatial distribution of photogenerated carriers in atomically thin MoS2 flakes and their correlation with photocurrent generation is investigated using Kelvin probe force microscopy. The study reveals that surface potential changes can image the vertical redistribution of photogenerated carriers, and the trapping of photogenerated holes at the interface between MoS2 and the substrate is the main mechanism for the photoresponse.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Chin Chyi Loo, Sha Shiong Ng, Wei Sea Chang
Summary: The recent progress in piezotronics and piezo-phototronics has revealed new methods for adjusting/enhancing the performance of GaN-based devices, and the photostrictive effect in GaN samples with InGaN/GaN MQWs can be elucidated through the combination of light-induced surface electric field and converse piezoelectric effect. The enhanced piezoelectric coefficient under laser illumination suggests the potential for adjustable photostrictive responses in optomechanical sensors/actuators by manipulating the strain state of MQWs.
Article
Chemistry, Physical
Yuuki Adachi, Yasuhiro Sugawara, Yan Jun Li
Summary: Probing CO on a rutile TiO2(110) surface using atomic force microscopy and Kelvin probe force microscopy enables the resolution of the interatomic dipole moment and charge state of CO at atomic resolution. The results suggest that both charge state and on-surface dipole interaction play a significant role in the reaction of CO on rutile TiO2(110) surface.
Article
Chemistry, Multidisciplinary
Chi Zhang, Jason M. Bartell, Jonathan C. Karsch, Isaiah Gray, Gregory D. Fuchs
Summary: A time-resolved near-field magnetic microscope based on magnetothermal interactions is developed, providing spatial resolution on the scale of 100 nm and a temporal resolution below 100 ps. This microscope offers an accessible and comparatively low-cost approach for nanoscale spatiotemporal magnetic microscopy in laboratories.
Article
Chemistry, Physical
Jie Mao, Zhenao Gu, Yue Yu, Huijuan Liu, Jiuhui Qu, Xiaoqiang An
Summary: This study integrated visual observation techniques and material synthesis strategies to reveal the structure-activity relationship of a single BiVO4 photocatalyst, confirming the significance of facet engineering for enhancing photocatalytic activity.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Minwoo Lee, Eunyoung Choi, Arman Mahboubi Soufiani, Jihoo Lim, Moonyong Kim, Daniel Chen, Martin Andrew Green, Jan Seidel, Sean Lim, Jincheol Kim, Xinchen Dai, Robert Lee-Chin, Bolin Zheng, Ziv Hameiri, Jongsung Park, Xiaojing Hao, Jae Sung Yun
Summary: This study presents an effective strategy to improve the performance of halide perovskite-based PV devices by using a hole-selective layer formed by PEAI salt, achieving high efficiency and stability under different light conditions.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Qin Ling, Qing Dai, Liu Yang, Like Huang, Xiaohui Liu, Houcheng Zhang, Jing Zhang, Yuejin Zhu, Ziyang Hu
Summary: This study investigates the spatial response of quasi-two-dimensional perovskites using complementary methods. The results reveal variations in the photovoltage across grains and grain boundaries, providing insight into the performance-limiting mechanisms and the development of efficient and stable 2D perovskite-based devices.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Chemistry, Physical
Mariano D. Jimenez-Sanchez, Nicoleta Nicoara, Jose M. Gomez-Rodriguez
Summary: The functionalization of AFM tips with Xe has been proven as an effective method to enhance resolution for intramolecular features. This study explores the adsorption of Xe on graphene on Pt(111) surfaces, laying the groundwork for in-situ tip functionalization with Xe on these surfaces. Results demonstrate the formation of well-ordered Xe islands in the submonolayer regime and the potential of using force spectroscopy to distinguish these islands from bare graphene areas.
APPLIED SURFACE SCIENCE
(2021)
Correction
Nanoscience & Nanotechnology
Cameron H. Parvini, M. A. S. R. Saadi, Santiago D. Solares
BEILSTEIN JOURNAL OF NANOTECHNOLOGY
(2021)
Article
Materials Science, Coatings & Films
Balaji Sompalle, Chun-Da Liao, Bin Wei, Maria de Fatima Cerqueira, Nicoleta Nicoara, Zhongchang Wang, Sascha Sadewasser, Pedro Alpuim
Summary: Hexagonal boron nitride (h-BN) is a crucial 2D insulator used in various applications, especially when grown using ammonia borane as a precursor. Its unique properties make it a promising material for a wide range of electronic and photonic devices. Understanding the synthesis process can help optimize production and scalability.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2021)
Article
Chemistry, Physical
Mariano D. Jimenez-Sanchez, Nour Sanchez-Abad, Nicoleta Nicoara, Jose M. Gomez-Rodriguez
Summary: In this study, the self-assembled structure and electronic structure of chloroaluminum phthalocyanines (ClAlPc) on graphene grown on Pt(111) surfaces were investigated using scanning tunneling microscopy (STM) under ultrahigh vacuum (UHV) and low-temperature conditions. Well-ordered molecular islands with rotational domains were observed in the submonolayer regime, with the ClAlPc molecules adopting a Cl-Up configuration. The correlation between molecular lattice orientation and graphene directions was identified, while no influence of the underlying moire ' patterns was found.
Article
Nanoscience & Nanotechnology
Berkin Uluutku, Enrique A. Lopez-Guerra, Santiago D. Solares
Summary: This study introduces a new method for obtaining material viscoelastic properties through the use of Z-transform without relying on specific models. The technique demonstrates good agreement between simulated and theoretical viscoelastic characteristics and offers a pathway for calculating standard viscoelastic responses. The Z-transform-based approach is shown to be complementary to model-based analyses and advantageous due to its generality and ability to handle unbounded inputs.
BEILSTEIN JOURNAL OF NANOTECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Bruna Silva, Joao Rodrigues, Balaji Sompalle, Chun-Da Liao, Nicoleta Nicoara, Jerome Borme, Fatima Cerqueira, Marcel Claro, Sascha Sadewasser, Pedro Alpuim, Andrea Capasso
Summary: Rhenium-based 2D transition metal dichalcogenides like ReSe2 were utilized to fabricate photodetectors, with CVD graphene single-crystal as lateral contacts, showing high photocurrent and responsivity. Introducing a CVD hexagonal boron nitride passivation layer further enhanced the device's optoelectronic performance.
Article
Materials Science, Multidisciplinary
Ishwor Khatri, Pedro Santos, Pedro Anacleto, Deepanjan Sharma, Mohamed Belmoubarik, Nicoleta Nicoara, Mutsumi Sugiyama, Sascha Sadewasser
Summary: The effect of selenium-free annealing on cesium fluoride-treated Cu(In,Ga)Se-2 thin films was studied, showing changes in surface morphology and chemical composition, as well as reduced Urbach energy. However, increased buffer/CIGS interface recombination due to alkali-containing layer re-evaporation limited the benefits of reduced Urbach energies. In contrast, CsF-treated CIGS thin films without annealing preserved the alkali-containing layer, leading to improved buffer/CIGS interface and significant improvements in open-circuit voltage and fill factor in solar cell devices.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2022)
Article
Biology
Cameron H. Parvini, Alexander X. Cartagena-Rivera, Santiago D. Solares
Summary: This article introduces an iterative viscoelastic approach for visualizing the time-dependent viscoelastic behavior of human skin cells. The results demonstrate clear differences in elasticity and viscosity between metastatic melanoma cells and normal cells, leading to a better understanding of cancer metastasis and aggression.
COMMUNICATIONS BIOLOGY
(2022)
Article
Physics, Applied
Berkin Uluutku, Marshall R. McCraw, Santiago D. Solares
Summary: Force-distance curve experiments are commonly used in atomic force microscopy to study the viscoelastic characteristics of materials. In this paper, a new method utilizing the modified discrete Fourier transform is proposed to directly approximate the storage and loss behavior of materials from experimental data. This model-free approach guides the selection of appropriate material models.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Marshall R. McCraw, Berkin Uluutku, Halen D. Solomon, Megan S. Anderson, Kausik Sarkar, Santiago D. Solares
Summary: This study investigates the limitations of time-dependent behavior resolution in atomic force microscopy force-distance experiments and proposes limits on the range of mechanical parameters that can be reliably obtained. The results show that the time domain is more restrictive than the frequency domain in the inversion process.
Article
Nanoscience & Nanotechnology
Santiago D. Solares, Alexander X. Cartagena-Rivera
Summary: Atomic force microscopy (AFM) is a powerful tool in the field of micro- and nanoscale science, but its adoption in healthcare applications is limited. This article explores the reasons for this and proposes integrating frequency-dependent nanomechanical measurements into healthcare strategies.
BEILSTEIN JOURNAL OF NANOTECHNOLOGY
(2022)
Article
Chemistry, Physical
Finn Babbe, Nicoleta Nicoara, Harvey Guthrey, Nathalie Valle, Omar Ramirez Sanchez, Damien Aureau, Hossam Elanzeery, Deepanjan Sharma, Jose Luis Virtuoso, Jean-Nicolas Audinot, Anastasiya Zelenina, Sevan Gharabeiki, Tom Wirtz, Susanne Siebentritt, Phillip J. Dale, Sascha Sadewasser, Diego Colombara
Summary: This study provides experimental evidence that the grain boundaries of sodium-doped CuInSe2 thin films may undergo reversible oxidation at room temperature, while undoped films may not. The findings are confirmed through various imaging and analysis techniques. These reactions raise new research questions about the role of alkali metal dopants and may lead to new breakthroughs in chalcopyrite solar cells.
ADVANCED ENERGY MATERIALS
(2023)
Article
Engineering, Mechanical
Maximilian Forstenhausler, Enrique A. Lopez-Guerra, Santiago D. Solares
Summary: This guideline provides detailed instructions for modeling linear viscoelastic materials under atomic force microscopy (AFM) characterization, aiming to complement existing literature and reach a broader audience. The document outlines procedures for setting up governing equations for material deformation by the AFM tip, accompanied by open-access code and Excel sheets. Despite its simplified approach, the algorithms presented are based on rigorous classical linear viscoelastic theory.
FACTA UNIVERSITATIS-SERIES MECHANICAL ENGINEERING
(2021)
Article
Materials Science, Multidisciplinary
Marcel S. Claro, Justyna Grzonka, Nicoleta Nicoara, Paulo J. Ferreira, Sascha Sadewasser
Summary: The 2D material beta-In2Se3 shows excellent material quality and device performance when grown on c-sapphire substrate, making it suitable for mass production of photodetectors.
ADVANCED OPTICAL MATERIALS
(2021)