Article
Materials Science, Multidisciplinary
Junhee Lee, Nari Hong, Woongki Hong, Duhee Kim, Yujin Hwang, Jaewon Jang, Hongki Kang
Summary: Various temperature sensitive biological mechanisms have been used in new biomedical engineering tools such as neuromodulation, cancer cell hyperthermia, or photothermal therapy. Transparent and high spatio-temporal resolution temperature sensors are needed to analyze biological effects accurately in response to temperature changes. Transparent temperature sensors with micro-scale spatial resolution are useful for cellular resolution bio-imaging, optical neural recording, and optical bio-modulation where transparency and high-resolution temperature sensing are required.
ADVANCED MATERIALS TECHNOLOGIES
(2022)
Article
Chemistry, Physical
Islam Mohammad Shafiqul, Toshiyuki Yoshida, Yasuhisa Fujita
Summary: Heterojunction light-emitting diodes (LEDs) based on p-type ZnO and n-type ZnMgO nanoparticles have been successfully fabricated. The experimental results show that the LEDs with the p-ZnO/n-ZnMgO/GZO structure exhibit better I-V characteristics and lower leakage current compared to the p-ZnO/GZO LEDs, and the emission intensity is improved by adding the ZnMgO NP layer.
Article
Chemistry, Physical
Avishek Banik, John Z. Tubbesing, Bin Luo, Xiaoting Zhang, Jay A. Switzer
Summary: The development of future optoelectronic materials relies on the high-performance p-type materials with optical transparency. Epitaxial growth of gamma-CuI on single crystalline Si(111) using a room-temperature electrochemical method demonstrates high in-plane and out-of-plane order. The deposition mechanism involves nucleating CuI seed crystals on n-Si(111) and simultaneous oxidation of Si to form SiOx, resulting in the lateral overgrowth of CuI seeds into a continuous film.
CHEMISTRY OF MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Chaolei Zuo, Sa Cai, Ziliang Li, Xiaosheng Fang
Summary: This study presents a transparent and self-powered photodetector based on a p-CuI/n-TiO2 heterojunction. The device exhibits a high on-off ratio and fast response speed, with a high sensitivity to ultraviolet light. This research provides a feasible approach for the construction of transparent, self-powered photodetectors based on p-n heterojunctions.
Article
Engineering, Electrical & Electronic
Parashurama Salunkhe, Prashant Bhat, Dhananjaya Kekuda
Summary: NiO/ZnO thin film heterojunction diodes were constructed using dc magnetron sputtering technique and their performance for ultraviolet sensor applications was evaluated. The device configuration, ITO/ZnO/NiO/Ag, showed excellent current-voltage rectifying characteristics at room temperature. The photodetector characteristics of the fabricated ITO/ZnO/NiO thin film stack were evaluated after rapid thermal annealing treatment. The diodes were tested under 365 nm UV light illumination and showed a fast response speed and stable photo detectivity in self-powered mode.
SENSORS AND ACTUATORS A-PHYSICAL
(2022)
Article
Physics, Condensed Matter
C. H. Raj Kishor, T. Sreelakshmy, Ankit Das, P. M. Aneesh
Summary: In this study, p-CuI/n-ZnO heterojunctions were fabricated using the solution-processed spin-coating technique. The structural, morphological, and optical properties of the CuI nanostructures, CuI and ZnO thin films were investigated. The results showed the formation of zinc blende gamma-CuI nanostructures and hexagonal wurtzite structure for the CuI and ZnO thin films, respectively. The J-V measurement confirmed the rectifying behavior of the heterojunctions, with a variation in the ideality factor observed at different voltage ranges.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Materials Science, Ceramics
Jun-Dar Hwang, Yan-Jhong Chiou, Wei-En Zeng
Summary: The NAN TCE exhibits higher transmittance but higher sheet resistance compared to the Al electrode in p-Si/n-ZnO HPDs, enhancing the photo response for UV and visible bands. The Ni diffusion in ZnO of NAN TCE suppresses defects and increases carrier mobility, leading to improved performance with significantly lower dark current and higher photo to dark current ratios.
CERAMICS INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Nikita Gagrani, Kaushal Vora, Sonachand Adhikari, Yuxin Jiang, Chennupati Jagadish, Hark Hoe Tan
Summary: This study investigates the electrical and optical properties of n-type tin oxide film and explores its application in InP nanowire light emitting diodes. The research finds that the device with lower resistance and higher absorption performs better in terms of output power.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Yi Huang, Jin Tan, Gang Gao, Jianmei Xu, Ling Zhao, Wei Zhou, Qing Wang, Shuoguo Yuan, Jian Sun
Summary: Ultraviolet photodetectors are attracting attention worldwide due to their applications in various fields. This study successfully fabricated ultrathin, ultra-high-transparency, and smooth CuI films using the copper film iodination method. The CuI films showed excellent optoelectronic properties and were used to construct photodetectors with promising applications in transparent and flexible electronic devices.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Engineering, Electrical & Electronic
Sanchari Banerjee, R. Thangavel
Summary: ZnO is a strategic material for photoelectrochemical water splitting. This study has adopted an efficient method to improve the photoelectric performance of ZnO by forming a heterostructure. The results show that the CuI/ZnO heterostructure achieves higher photocurrent density and photoconversion efficiency.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Engineering, Electrical & Electronic
Jun-Dar Hwang, Meng-Chi Lin
Summary: Due to the small valence band discontinuity at NiO/Si interface, the p-NiO/n-Si heterojunction photodiodes have poor UV detection. However, by sandwiching a ZnO layer between p-NiO and n-Si, the UV response is largely enhanced due to the large valence band discontinuity at ZnO/Si interface. The ZnO layer also suppresses the dark current and increases the detectivity of the photodiodes.
SENSORS AND ACTUATORS A-PHYSICAL
(2023)
Article
Chemistry, Physical
Naveen Kumar, Umme Farva, Malkeshkumar Patel, Wu-Shin Cha, Jaehyeong Lee, Joondong Kim
Summary: In this study, a novel, eco-friendly sputtergrown p-n heterojunction thin-film device utilizing n-Ga2O3 and p-SnS was proposed and investigated for transparent photovoltaic (TPV) applications. By optimizing the thickness of Ga2O3 thin-film, the device achieved high photocurrent density and open-circuit voltage, demonstrating excellent photovoltaic performance.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Multidisciplinary
Yibo Niu, Yu Wang, Linli He, Yujie Wang, Huizhen Ma, Nan Li, Danli Xie, Jianshan Ye, Ying Ma
Summary: In this study, a simple in-situ growth strategy was developed to synthesize a CuI/Porphyrin-based graphdiyne (PDY) p-n heterojunction photocathode, which exhibited excellent photoelectrochemical performance and was capable of detecting L-Cys with a wide linear range and low detection limit.
MATERIALS TODAY CHEMISTRY
(2023)
Article
Optics
Pawan Kumar, Sahana Nagappa Moger, Gowrish K. Rao, M. G. Mahesha
Summary: In this study, three functional heterojunctions based on SnS were fabricated using the low-cost SILAR technique, and detailed analysis was conducted. The experimental results showed that the n-SnO2/p-SnS heterojunction exhibited significant photo response and excellent photodetection figures of merit.
OPTICS AND LASER TECHNOLOGY
(2024)
Article
Nanoscience & Nanotechnology
Shouzhe Feng, Yujie Zhang, Pengjie Zhang, Jun Cao, Jingjing Wang, Yingying Zheng, Lei Shi, Jiaqi Pan, Chaorong Li
Summary: In this study, a CuI/BaSnO3 quantum dot (QD)/ZnSnO3 perovskite-based transparent p-n junction was prepared using a hybrid approach. The resulting p-n junction showed high transmittance and photovoltaic enhancement, leading to a respectable photovoltaic conversion efficiency. The stability of the p-n junction over a long period of time was also demonstrated. The remarkable performance can be mainly attributed to the use of BaSnO3 QD and the presence of additional hole-related carriers caused by Cu vacancy.
ACS APPLIED NANO MATERIALS
(2023)
Article
Physics, Applied
Sijun Luo, Lukas Trefflich, Susanne Selle, Ron Hildebrandt, Evgeny Krueger, Stefan Lange, Jingjing Yu, Chris Sturm, Michael Lorenz, Holger Von Wenckstern, Christian Hagendorf, Thomas Hoeche, Marius Grundmann
Summary: This paper reports the heteroepitaxial growth of (00.1)-oriented Zn2GeO4 thin films on c-plane sapphire substrates using pulsed laser deposition. The thin films exhibit [11.0] Zn2GeO4// [11.0] Al2O3 and [1(1) over bar.0] Zn2GeO4//[1(1) over bar.0] Al2O3 in-plane orientation relationships. The measured properties include a rocking curve full width at half maximum of 0.35 degrees, a direct bandgap of 4.9 +/- 0.1 eV, and a defect-related photoluminescence emission centered at 2.62 eV with a FWHM of 0.55 eV. This study enhances our understanding of the physical properties and potential device application of Zn2GeO4 thin films.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Tillmann Stralka, Michael Bar, Fabian Schoeppach, Susanne Selle, Chang Yang, Holger von Wenckstern, Marius Grundmann
Summary: Current probe atomic force microscopy (cp-AFM) measurements reveal the influence of the textured nature of sputtered gamma-CuI (111) thin films on charge carrier transport. The conductive behaviors of grains and grain boundaries (GBs) are differentiated and correlated, showing a clear difference between them. The time-dependent surface changes, possibly caused by atmospheric oxygen, result in the vanishing of charge carrier transport over time.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Sofie Vogt, Clemens Petersen, Max Kneiss, Daniel Splith, Thorsten Schultz, Holger von Wenckstern, Norbert Koch, Marius Grundmann
Summary: This study presents the structural and electrical properties of undoped and doped alpha-Ga2O3 thin films grown on m-plane sapphire. An undoped alpha-Ga2O3 buffer layer was introduced to improve crystal quality and stabilize the alpha-phase at lower substrate temperatures. Donor doping with tin and germanium achieved high electron mobilities. Suitable annealing temperature for ohmic Ti/Al/Au layer stacks was identified, while high annealing temperatures deteriorated the electrical properties of the thin films, indicating the need for low temperature contacting procedures for alpha-Ga2O3-based devices.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Physics, Condensed Matter
Evgeny Krueger, Volker Gottschalch, Gabriele Benndorf, Ron Hildebrandt, Ana Lucia Pereira, Michael S. Bar, Steffen Blaurock, Stefan Merker, Chris Sturm, Marius Grundmann, Harald Krautscheid
Summary: This study presents the epitaxial growth of AgxCu1-xI alloy layers and isolated small crystals on Al2O3 (0001) using the close distance sublimation (CDS) technique. Single-phase gamma-AgxCu1-xI thin films are obtained up to an Ag content of approximately 0.5, with the beta-phase also observed at higher Ag contents. The epitaxial relationships between the deposited AgxCu1-xI layers and the Al2O3 substrate, as well as the structure type, are discussed for different alloy compositions. Additionally, a method for depositing polycrystalline single-phase gamma-AgxCu1-xI thin films for Ag contents up to approximately 0.7 is presented based on the solid-state reaction of AgI layers on Al2O3 (0001) substrate with CuI. Furthermore, it is shown that the near-band-edge emission at 2 K is dominated by excitonic recombination, and the spectral position of the emission profile can be tuned by the alloy composition.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2023)
Article
Nanoscience & Nanotechnology
Jon Borgersen, Robert Karsthof, Vegard Ronning, Lasse Vines, Holger von Wenckstern, Marius Grundmann, Andrej Yu Kuznetsov, Klaus Magnus Johansen
Summary: Significant resistivity variations have been observed in oxides subjected to low ion doses, which cannot be explained by bulk defects. A comparative study of In2O3-based oxides revealed correlations between resistivity evolution, low ion doses, and UV illumination. The resistivity drops were attributed to oxygen desorption facilitated by irradiation/illumination, as confirmed by post-irradiation exposure to oxygen atmosphere.
Review
Materials Science, Coatings & Films
Laurenz Thyen, Daniel Splith, Max Kneiss, Marius Grundmann, Holger von Wenckstern
Summary: We introduce a new technique, MARS-PLD, for area-selective physical vapor deposition. By using a movable mask, we can selectively mask any desired area on a substrate to create multinary material composition gradients. We demonstrated the capabilities of this method by fabricating material gradients in (Mg,Zn)O thin films and on predefined two-dimensional patterns.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Nanoscience & Nanotechnology
Evgeny Krueger, Michael Seifert, Volker Gottschalch, Harald Krautscheid, Claudia S. Schnohr, Silvana Botti, Marius Grundmann, Chris Sturm
Summary: We studied the excitonic transition energy E-0 and spin-orbit split-off energy Delta(0) of gamma-AgxCu1-xI alloy thin films using reflectivity measurements at temperatures between 20 K and 290 K. The observed bowing behavior of the E-0 transition as a function of alloy composition is explained based on first-principles band structure calculations. The spin-orbit coupling increases with increasing Ag-content, and the temperature-dependent bandgap shift decreases with increasing Ag-content.
Article
Physics, Applied
Andreas Mueller, Sebastian Henn, Evgeny Krueger, Steffen Blaurock, Harald Krautscheid, Marius Grundmann, Chris Sturm
Summary: We report on the photoluminescence emission in copper iodide bulk single crystals induced by two- and three-photon absorption around 1.525eV. The non-linear optical processes were investigated through density-dependent, steady-state, and time-resolved photoluminescence spectroscopy. We observed that the photoluminescence intensity showed an almost parabolic behavior with the excitation power when the excitation energy corresponded to half of the bandgap energy. We also found a cubic contribution that increased with decreasing excitation energy. The ratio between the two- and three-photon absorption cross sections was determined to be approximately 10(-28) cm(2)s.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Condensed Matter
Marius Grundmann
Summary: This study revisits the problem of potential, electrical field, and charge density in a space charge region. Using the Boltzmann approximation, an analytical asymptotic solution is obtained. The exact solution can be found by numerically integrating an analytical function. A comparison is made with the popular abrupt (or depletion) approximation, and an analytical approximation is provided. The analytical approximation for potential, electrical field, and charge density in a space charge (depletion) region shows good agreement with the (numerically) exact solution.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2023)
Article
Instruments & Instrumentation
Michael Lorenz, Holger Hochmuth, Holger von Wenckstern, Marius Grundmann
Summary: Pulsed laser deposition (PLD) is a highly flexible physical growth technique for thin films of functional materials. This article describes a relatively simple and reliable concept of PLD hardware that enables deposition on large areas (up to 4 inches in diameter) and tailored lateral and vertical composition spreads without the need for time-consuming hardware changes. Different PLD approaches have been implemented in various chambers by using specific and correlated computer-controlled movements of the target, substrate, and masks, along with an appropriate target phase composition.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2023)
Article
Nanoscience & Nanotechnology
Fabian Schoeppach, Daniel Splith, Holger von Wenckstern, Marius Grundmann
Summary: In this study, metal-semiconductor field-effect transistor (MESFET) devices based on pulsed laser deposition (PLD) grown In2O3 thin films are reported. These devices exhibit on-off ratios exceeding 6 orders of magnitude and low sub-threshold swing values close to the thermodynamic limit. Oxygen plasma treatment and compensation doping with Mg are used to suppress the accumulation of electrons at the surface of In2O3, which is a major obstacle for its use as an active material in electronic devices.
ADVANCED ELECTRONIC MATERIALS
(2023)
