Article
Chemistry, Physical
Yang Chen, You Wu, Jianwei Ben, Ke Jiang, Yuping Jia, Shanli Zhang, Hang Zang, Zhiming Shi, Bin Duan, Xiaojuan Sun, Dabing Li
Summary: A new type of ultraviolet photodetector was fabricated by integrating GaN nanoparticles as the absorber and graphene as the carrier transport channel. The GaN nanoparticles provide trap states for the photo-generated hole, while graphene has high carrier mobility, leading to improved detector performance. This combination results in a UV photodetector with high responsivity and persistent photoconduction effect.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Haijuan Wu, Lingyan Liang, Xiaolong Wang, Xixiu Shi, Hengbo Zhang, Yu Pei, Wanfa Li, Bo Sun, Cai Shen, Hongtao Cao
Summary: Achievement of high-performance p-channel copper iodide (CuI) thin-film transistors (TFTs) with a bottom-gate structure is demonstrated by replacing SiO2 dielectric with Chitosan (CS), resulting in a threshold voltage of -0.35 V, a field-effect mobility (WFE) up to 60 cm2V- 1s- 1, and an on/off current ratio (Ion/Ioff) beyond 103. CuI films on CS-dielectrics exhibit a smoother surface morphology, tinier grains, higher packing density, and a lower work function compared to those on SiO2, leading to enhanced performance. Low process temperature (<50 C) enables the realization of flexible and transparent CuI TFTs with comparable performance to those on rigid ITO glass. Moreover, complementary inverters composed of p-type CuI and n-type ITO TFTs exhibit clear inverting characteristics and voltage gain of over 20.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
G. D. Yuzuak, M. M. Cicek, Y. Elerman, E. Yuzuak
Summary: The thermoelectric effect is an efficient method for converting waste heat into electrical energy, with p-type BiSbTe thin films showing promise for future technological applications. Using chromium as an adhesion and seed layer can significantly enhance the electrical transport properties of BiSbTe films by controlling microstructure and transport properties.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Multidisciplinary
Satoshi Ishii, Min-Wen Yu, Kuo-Ping Chen, Tadaaki Nagao
Summary: This study experimentally demonstrates that non-metallic plasmonic material zirconium nitride (ZrN) can generate electric potential through plasmoelectric effect, providing possibilities for robust photoelectric devices working at off-resonances.
ADVANCED MATERIALS INTERFACES
(2023)
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, Multidisciplinary
Yu Luo, Weitao Su, Juanjuan Zhang, Fei Chen, Ke Wu, Yijie Zeng, Hongwei Lu
Summary: The study proposes a new method that combines tip-enhanced Raman spectroscopy (TERS) with Kelvin probe force microscopy (KPFM) to investigate the localized electronic properties of 2D materials. By measuring strain distribution, the spatial resolution of contact potential difference (CPD) measurements can be enhanced.
Article
Engineering, Electrical & Electronic
Kenta Nakazawa, Kengo Fukazawa, Takeshi Uruma, Gen Hashiguchi, Futoshi Iwata
Summary: An imaging method using Kelvin probe force microscope was developed to evaluate the surface potential distribution of highly charged micro-sized samples, which is crucial for the assessment of electret films in electrostatic induction-type energy harvesters.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2022)
Review
Chemistry, Multidisciplinary
Liu Yang, Yanyan Wang, Xu Wang, Shareen Shafique, Fei Zheng, Like Huang, Xiaohui Liu, Jing Zhang, Yuejin Zhu, Chuanxiao Xiao, Ziyang Hu
Summary: This review focuses on the application of atomic force microscopy (AFM)-based scanning probing techniques in investigating the local properties of polycrystalline photovoltaic materials. By studying the optoelectronic heterogeneities at grain interiors (GIs) and grain boundaries (GBs), it is possible to understand their critical roles in device performance and guide optimization. The potential of these AFM-based techniques in developing next-generation photovoltaics and optoelectronics is also discussed.
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
Engineering, Electrical & Electronic
Wenhao Zhang, Xiqi Wu, Wenting Wang, Kaidi Zhang, Bowen Li, Yuhang Chen
Summary: The on-demand modulation of material properties at the nanoscale is crucial for the development of functional micro- and nanodevices. This study focuses on modulating the structural and electric properties of vanadium dioxide (VO2) films using a locally confined atomic force microscope (AFM) tip-induced electric field. The time stability and reversibility of the modulation are investigated, and potential applications in developing optoelectronic devices with arbitrary shapes are demonstrated.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
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
Yin-Wei Cheng, Chun-Hung Chen, Shih-An Wang, Yi-Chang Li, Bo-Liang Peng, Jun-Han Huang, Chuan-Pu Liu
Summary: This study investigates the effects of boron and arsenic doping on the performance of silicon thin film anode materials in lithium-ion batteries. The results show that boron and arsenic can respectively deteriorate and enhance the capacity retention and rate capabilities of the pristine materials.
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
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
Physics, Applied
Arief Udhiarto, Ratno Nuryadi, Miftahul Anwar, Gaurang Prabhudesai, Daniel Moraru
Summary: Non-degenerately doped lateral nanoscale p-n and p-i-n silicon-on-insulator devices have been successfully fabricated and characterized, demonstrating the achievement of negative differential transconductance (NDT) and sharp current increase due to band-to-band tunneling (BTBT) mechanism.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Applied
Chitra Pandy, Gaurang Prabhudesai, Kensuke Yamaguchi, V. N. Ramakrishnan, Yoichiro Neo, Hidenori Mimura, Daniel Moraru
Summary: In this study, the electron transport through a few-donor cluster flanked by acceptors in gated Si-nanowire transistors with n(+) electrostatically-doped source/drain was investigated using first-principles and semi-empirical simulations. The results show that acceptor-atoms mainly shift the cluster potential, introducing a minor distortion to its energy spectrum. This distortion is relatively independent of the position of the acceptor-atoms and systematically depends on their number.
APPLIED PHYSICS EXPRESS
(2021)
Article
Physics, Applied
Taruna Teja Jupalli, Ananta Debnath, Gaurang Prabhudesai, Kensuke Yamaguchi, P. Jeevan Kumar, Yukinori Ono, Daniel Moraru
Summary: In this study, a comparative analysis was conducted on nano-scale silicon-on-insulator transistors with phosphorus-doped channels under two different doping concentrations. It was found that devices with higher dopant concentrations can achieve single-electron tunneling operation at room temperature, while devices with lower concentrations are limited to around 100K. Numerical simulations showed that donor clustering plays a dominant role in the formation of quantum dots, with clusters consisting of more than three donors responsible for room-temperature operation.
APPLIED PHYSICS EXPRESS
(2022)
Article
Chemistry, Physical
Rohitkumar Shailendra Singh, Katsuyuki Takagi, Toru Aoki, Jong Hyun Moon, Yoichiro Neo, Futoshi Iwata, Hidenori Mimura, Daniel Moraru
Summary: Carbon nanotube (CNT) bundles can be used to build hybrid CMOS-compatible devices on Si nanostructures. By using inkjet printing, we fabricated semiconductor single-walled CNT field-effect transistors on a CMOS-compatible platform. We developed a method to produce stable CNT solutions without surfactants, allowing for the dispersion of CNT bundles in the source-drain gaps of the transistors, providing paths for current flow.
Article
Chemistry, Multidisciplinary
Pooja Yadav, Soumya Chakraborty, Daniel Moraru, Arup Samanta
Summary: Experimental and theoretical analysis of current-voltage characteristics of a quantum dot in a silicon transistor's nanoscale channel revealed quantum Coulomb blockade phenomenon and detectable effect of variable tunnel barriers. A new formalism was developed to replicate the experimental results by modifying the rate-equation approach, supporting features of small-scaled SET devices.
Article
Engineering, Electrical & Electronic
Pooja Yadav, Soumya Chakraborty, Daniel Moraru, Arup Samanta
Summary: We report the finite-bias characteristics of electrical transport through phosphorus donors in silicon nanoscale transistors, with the observation of inelastic cotunneling current in the Coulomb-blockade region. The cotunneling current appears as a resonant-tunneling current peak emerging from the excited state and sustained within the blockade regions. This unique cotunneling feature is ascribed to excitation-related inelastic cotunneling involving the ground and excited states. Theoretical calculations for a two-level quantum dot support our experimental observation.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2023)
Article
Chemistry, Analytical
Haoran Mu, Daniel Smith, Tomas Katkus, Darius Gailevicius, Mangirdas Malinauskas, Yoshiaki Nishijima, Paul R. Stoddart, Dong Ruan, Meguya Ryu, Junko Morikawa, Taras Vasiliev, Valeri Lozovski, Daniel Moraru, Soon Hock Ng, Saulius Juodkazis
Summary: Microlens arrays (MLAs) were fabricated using a femtosecond direct laser write (fs-DLW) technique, allowing high-fidelity definition of 3D surfaces on IR transparent substrates. A graphene oxide (GO) grating acting as a linear polariser was also fabricated by fs-DLW. The MLAs and GO polarisers were characterised and their performance was simulated through numerical modelling with good agreement between experimental results and simulations.
Article
Chemistry, Multidisciplinary
Denver Linklater, Arturas Vailionis, Meguya Ryu, Shuji Kamegaki, Junko Morikawa, Haoran Mu, Daniel Smith, Pegah Maasoumi, Rohan Ford, Tomas Katkus, Sean Blamires, Toshiaki Kondo, Yoshiaki Nishijima, Daniel Moraru, Michael Shribak, Andrea O'Connor, Elena P. Ivanova, Soon Hock Ng, Hideki Masuda, Saulius Juodkazis
Summary: In this article, we provide an overview of structural and optical characterization techniques that are useful for biomaterials. These techniques allow for new insights into the structure of natural fibers, such as spider silk, with minimal sample preparation. By utilizing electromagnetic radiation over a broad range of wavelengths, information about material structure at different length scales can be obtained. Additionally, polarization analysis of optical images can provide further information on feature alignment when optical characterization is not sufficient.
Article
Chemistry, Multidisciplinary
Daniel Moraru, Tsutomu Kaneko, Yuta Tamura, Taruna Teja Jupalli, Rohitkumar Shailendra Singh, Chitra Pandy, Luminita Popa, Felicia Iacomi
Summary: Researchers have made breakthroughs in the field of silicon nano-electronics, showing that single-charge tunneling can be achieved by codoping phosphorus and boron. This improves the electron transport properties in nanostructures used in transistors and diodes, and enhances the functionality of the devices.
Article
Optics
Daniel Smith, Soon Hock Ng, Amanda Tang, Tomas Katkus, Daniel Moraru, Saulius Juodkazis
Summary: Ultra-short laser pulses were used to laser ablate the surface of crystalline sapphire at high intensity. Annealing at high temperature led to surface reconstruction and reduction of surface roughness. The 3D shape of a micro-lens was not altered after annealing.
Article
Materials Science, Multidisciplinary
Shuji Kamegaki, Daniel Smith, Meguya Ryu, Soon Hock Ng, Hsin-Hui Huang, Pegah Maasoumi, Jitraporn Vongsvivut, Daniel Moraru, Tomas Katkus, Saulius Juodkazis, Junko Morikawa
Summary: A four-polarisation camera was used to map the absorbance of olivine micro-grains before and after high-temperature annealing. It was found that high-temperature annealing caused magnetization of olivine xenoliths. Different operating modes of the polariscope were used to validate the three-point fit method for analyzing the birefringence and absorbance of the samples in transmission and reflection modes.
Article
Engineering, Electrical & Electronic
Miftahul Anwar, Teguh E. Saraswati, Lia Anjarwati, Daniel Moraru, Arief Udhiarto, Feri Adriyanto, Hari Maghfiroh, Ratno Nuryadi
Summary: This study investigates the characteristics of plasma ionization during plasma arc discharge in water using carbon electrodes. The arc shape and voltage oscillation are observed using a digital camera and current and voltage vs. time characteristics. The ionization energy is calculated using simultaneous measurement data and compared with optical emission spectroscopy data. The results show four types of arc discharge and the ability to measure ionization energy within and outside the 1-4 eV range. This study reveals the possibility of using simultaneous measurements to investigate plasma ionization characteristics.
MICRO AND NANO ENGINEERING
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
G. Prabhudesai, K. Yamaguchi, M. Tabe, D. Moraru
2020 IEEE SILICON NANOELECTRONICS WORKSHOP (SNW)
(2020)
