Article
Chemistry, Multidisciplinary
Yujie Huang, Jing Yang, Degang Zhao, Yuheng Zhang, Zongshun Liu, Feng Liang, Ping Chen
Summary: The dark leakage current of AlxGa1-xN Schottky barrier detectors with different Al contents was investigated. It was found that the dark leakage current increased with increasing Al content. XRD and SIMS results showed no significant difference in dislocation density and carbon impurity concentration among the samples, indicating that they were not the main reason for the difference in dark leakage current. However, positron annihilation results revealed an increase in vacancy defect concentration with increasing Al content, which was consistent with the increase in dark leakage current. This discovery is important for accurately controlling the performance of AlxGa1-xN detectors.
Article
Engineering, Electrical & Electronic
Benjamin K. Korir, Joshua K. Kibet, Silas M. Ngari
Summary: This study presents a low-cost dye-sensitized solar cell architecture without expensive hole transport layers, using a metallic layer for dye regeneration. Through thorough analysis and numerical simulations, ZnOS is identified as a superior ETL material compared to TiO2, showing promise for future design and manufacture of HTL-free DSSCs.
JOURNAL OF ELECTRONIC MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Takaya Kawagishi, Yusuke Adachi, Taizo Kobayashi
Summary: This study investigates the impact of different crystallographic structures of sputter-deposited TiO2 n-type window layers on the power conversion of TiO2/Se photovoltaic devices. The efficient photovoltaic conversion of TiO2/Se devices requires improving carrier collection in the Se layer and reducing recombination at the TiO2/Se interface. TiO2 window layers with varying anatase and rutile crystallographic structures were applied to TiO2/Se heterojunction devices. The power conversion efficiency of TiO2/Se photovoltaic devices was increased from 3.04% to 4.48% in devices with anatase/rutile mixture window layer.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Multidisciplinary Sciences
Morteza Ahmadi, Masoud Abrari, Majid Ghanaatshoar
Summary: The study proposes and fabricates a heterojunction between Al-doped ZnO and (Mg, N)-doped CuCrO2 thin films using sputtering deposition method, achieving an efficient UV photovoltaic photodetector with fast response, high photosensitivity, responsivity, and detectivity compared to traditional photoconductors.
SCIENTIFIC REPORTS
(2021)
Article
Physics, Condensed Matter
Naveen Kumar, Subhash Chand
Summary: The study found that the Schottky emission mechanism dominates in non-saturation reverse current in the Ni/SiO2/p-Si/Al structure at temperatures ranging from 200-300K. As the temperature decreases, the barrier height increases, leading to a decrease in reverse current.
SUPERLATTICES AND MICROSTRUCTURES
(2021)
Article
Materials Science, Multidisciplinary
Luanhong Sun, Yijie Zhao, Yuanfeng Ye, Lingyun Hao, Wei Wang, Hangmin Guan, Jinze Li
Summary: A convenient and effective strategy for Ga doping is proposed to suppress defects and tailor the residual stress of CZTSSe thin film solar cells. The CZTGSSe with a doping concentration of 0.28 mol L-1 exhibits an optimized heterojunction characteristic with a CBO of -0.30 eV and a released residual stress of -1.87 GPa. The ultimately structured device achieves a PCE of 5.37% and maintains 80% of its original PCE after exposure to a harsh bending environment.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Chemistry, Physical
Sixue Chen, Pu Qin, Jianxing Yang, Mingming Chen, Qianqian Du, Youchao Kong, Yuan Liu, Dawei Cao
Summary: Recently, the growth of ferroelectric HfO2 thin films through Al doping has been demonstrated. The structural analysis showed the formation of non-centrosymmetric polar orthorhombic phase HfO2 after Al doping. The ferroelectricity was found to be dependent on the Al composition, with a remnant polarization of 22.9 μC/cm2 obtained in HfO2 thin film doped with 5.0 mol% Al. The mechanisms of structural transition and generation of oxygen vacancies due to Al doping were further studied.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Qiaolu Lin, Nannan Xu, Gongping Li, Zhengfang Qian, Huan Liu, Renheng Wang
Summary: In this study, different systems of Cu-doped TiO2 were calculated to understand the magnetic properties, showing that the substitution ratio and defects can affect the ferromagnetic behavior. The interaction between Cu substitution, oxygen vacancy, and carrier-induced polarization were found to be key factors in determining the ferromagnetism in the material.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Chemistry, Physical
Vitaly Gurylev, Tzu-Kang Chin, Artur Useinov
Summary: The study investigated the correlation between field emission characteristics of TiO2@CNTs nanocomposite and TiO2 crystallinity by charge transfer mechanism. Results showed that CNTs covered with amorphous TiO2 exhibited the best field emission properties due to more efficient charge transfer caused by oxygen vacancies in amorphous TiO2.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Neelima Singh, Alpana Agarwal, Mohit Agarwal
Summary: The study investigates the effect of band offsets engineering for lead-free all-inorganic double-perovskite solar cell and finds that within a certain range, the conduction band offset and valence band offset can improve device performance. The optimal combination of electron transport layer and hole transport layer is proposed to further enhance the overall power conversion efficiency of the cell.
Article
Materials Science, Multidisciplinary
Mohammad M. Qaid, Mohamad S. AlSalhi
Summary: This study investigates the leakage current and charge transport mechanism in the ultrathin insulating polymer PPO using TiN and 3D carbon nanosheets as conducting electrodes. The dominant Schottky emission mechanism in PPO indicates low charge trap density, allowing for extraction of key parameters such as Schottky barrier height and polymer dielectric constant. The similarity in charge transport mechanisms between PPO and high-k nonorganic insulators suggests potential integration of this polymer into various microelectronic devices.
MATERIALS CHEMISTRY AND PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Atul Kumar, R. Thandaiah Prabu, Avirup Das
Summary: An SnS/CdS heterostructure-based solar cell has been simulated and optimized to improve its efficiency. The optimized device configuration provides a crucial guideline for experimentalists to fabricate high-efficiency SnS solar cells.
OPTICAL AND QUANTUM ELECTRONICS
(2022)
Article
Energy & Fuels
Mohsen Jahandardoost, Curtis Walkons, Shubhra Bansal
Summary: A parametric study was conducted on Cu(In,Ga)(S,Se)2 solar cells using SCAPS-1D simulator to investigate the effects of bulk and interface properties on device characteristics under different heat and light stress conditions. The study considered various variables and their interdependencies, such as conduction band offset, buffer ionized donor density, CIGS shallow acceptor density, CIGS deep acceptor density, CIGS shallow donor density, ionized acceptor concentration in the CIGS/buffer interface, and back contact work-function. The results showed that changes in absorber properties and interface defect density have significant impacts on open-circuit voltage and carrier density. The study also revealed the sensitivity of minimum depletion width and inflection in capacitance-voltage curves to certain parameters near the back contact.
Article
Materials Science, Multidisciplinary
Marwa S. Salem, Ahmed Shaker, Mohamed S. Othman, Amal H. Al-Bagawia, Mostafa Fedawy, Ghada Mohamed Aleid
Summary: The study identifies antimony sulfide (Sb2S3) as a suitable absorber material for thin film solar cells, but current issues lead to poor photovoltaic performance. To enhance the power conversion efficiency, design guidelines are proposed using device simulation, resulting in an optimized PCE of around 22%.
Article
Engineering, Electrical & Electronic
Luanhong Sun, Wei Wang, Lingyun Hao, Zhichao Jia, Yijie Zhao, Guowei Zhi, Hanyu Yao
Summary: Synthesizing Cu2CdxZn1-xSn(S,Se)(4) (CCZTSSe) absorber through selenizing Cd2+ treated CZTS precursor significantly increases the grain size from nano to micron level, leading to enhanced device performance. The improved heterojunction characteristic with CdS buffer layer in CCZTSSe prevents carrier recombination caused by interface state defects, resulting in an optimized device efficiency of 4.38% for x = 0.07.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Jenam Kim, Young Uk Ryu, Ae Jin Lee, Ye Won Kim, Ji Hyeon Hwang, Youngjin Kim, Hansol Oh, YongJoo Park, Woojin Jeon
Summary: This study investigates the deposition of homogeneous ZrxHf(1-x)O2 thin films using a mixed precursor mixture by atomic layer deposition (ALD) and explores their electrical properties. It is found that the mixed structures of ZrO2/HfO2 thin films deposited by ALD remain inhomogeneous even after annealing, resulting in part of the HfO2 remaining in the monoclinic phase and reducing the dielectric constant. The study also discovers that ZrxHf1-xO2 thin films prepared using CpZr and CpHf precursors exhibit enhanced electrical properties.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2022)
Article
Nanoscience & Nanotechnology
Nahid Sultan Al-Mamun, Douglas E. Wolfe, Aman Haque, Jae-Gyun Yim, Seong Keun Kim
Summary: A room temperature annealing method using electron impulse force is demonstrated to significantly improve the crystallinity and reduce the resistivity of tin disulfide, which is important for post-synthesis annealing applications that require high temperature and special environments.
SCRIPTA MATERIALIA
(2023)
Article
Nanoscience & Nanotechnology
Jaegyun Yim, Hong Keun Chung, Seung Ho Ryu, Han Kim, Sung Ok Won, Taeyong Eom, Taek-Mo Chung, Seong Keun Kim
Summary: This study demonstrates the area-selective atomic layer deposition (ALD) of SnS2 on SiO2 and Al2O3 surfaces. By optimizing the super-cycle conditions, selective SnS2 deposition of approximately 7 nm thickness was achieved on both SiO2 and Al2O3. This method contributes to the improvement of area-selective deposition technology for BEOL-compatible transistors.
ACS APPLIED NANO MATERIALS
(2023)
Article
Physics, Applied
Jihoon Jeon, Song-Hyeon Kuk, Ah-Jin Cho, Seung-Hyub Baek, Sang-Hyeon Kim, Seong Keun Kim
Summary: We have fabricated n-type ferroelectric field-effect transistors (FeFETs) using atomic-layer-deposited HfZrOx (HZO) films with a large memory window (MW) immediately after the write operation. Charge trapping at the HZO/Si interface in FeFETs is identified as the main cause of memory window reduction. By controlling the properties of the interfacial layer through varying the O-3 injection time during atomic layer deposition, the FeFETs based on HZO (long O-3 of 7 s) exhibit a larger MW (2.1 V) compared to the FeFETs based on HZO (short O-3 of 0.3 s) (0.9 V). Pulsed I-V measurements confirm that the FeFETs based on HZO (long O-3 of 7 s) show a large MW of 1.0 V with an extremely short delay time of 100 ns between pulses. The improvement in the performance of HZO-based FeFETs suggests a reduction in trap density in the interfacial layer by using a long O-3 injection time.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Dong Hee Han, Ae Jin Lee, Min Kyeong Nam, Seungwoo Lee, Su Jin Choi, Youngjin Kim, Taehwan Moon, Woojin Jeon
Summary: The ferroelectric properties of Hf0.5Zr0.5O2(HZO) were investigated based on the preferred orientations of the titanium nitride (TiN) bottom electrode (BE). (111) and (200)-oriented TiN were used as BEs. The difference in crystallinity of HZO was observed and its electrical properties were compared. Through various crystal structure analyses and electrical measurements, it was found that the HZO thin film grown on TiN(200) had more ferroelectric non-centrosymmetric orthorhombic phase in the pristine state due to the local epitaxial relation between TiN(200) and HZO.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Chemistry, Physical
Sung-Jin Jung, Sang-Soon Lim, Byeong-Hyeon Lee, Sung Ok Won, Hyung-Ho Park, Seong Keun Kim, Jin-Sang Kim, Seung-Hyub Baek
Summary: Solid compounds with volatile elements often deviate from stoichiometric composition during thermal processes, leading to varied properties. Understanding the effect of process parameters on element volatility and how physical properties change with altered stoichiometry is crucial.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Engineering, Electrical & Electronic
Myeong Gil Chae, Jina Kim, Hee Won Jang, Bo Keun Park, Taek-Mo Chung, Seong Keun Kim, Jeong Hwan Han
Summary: High-performance p-type thin-film transistors (TFTs) with high field-effect mobility and high on/off current ratios (Ion/Ioff) were achieved by engineering the microstructure and surface morphology of the atomic layer-deposited (ALD) SnO channel layer. ALD SnO films grown at 225 degrees C exhibited excellent crystallinity and dense, smooth surfaces, resulting in superior field-effect mobility of 6.13-7.24 cm2/V·s without requiring high-temperature post-annealing. Optimization of the SnO channel thickness suppressed off-state leakage current and yielded excellent TFT switching performance with an Ion/Ioff value of 104-105. ALD Al2O3 film backchannel passivation improved subthreshold swing characteristics by reducing surface defect states, highlighting the importance of synergistic control of microstructure, surface morphology, and thickness in ALD SnO channels for high-performance p-type SnO TFTs.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Physics, Applied
Seung Ho Ryu, Jihoon Jeon, Gwang Min Park, Taikyu Kim, Taeyong Eom, Taek-Mo Chung, In-Hwan Baek, Seong Keun Kim
Summary: In this study, the researchers enhanced the performance of p-type SnO thin-film transistors (TFTs) by using an atomic-layer-deposited SnO/high-k structure with crystalline HfO2 as a high-k dielectric. The introduction of an ultrathin Al2O3 layer on the surface of c-HfO2 effectively eliminated grain boundaries and improved the electrical performance of the TFTs. This finding suggests the potential of combining van der Waals semiconductors with high-k dielectrics for advanced device applications.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Ceramics
Seunghyeok Lee, Sung-Jin Jung, Gwang Min Park, Junpyo Hong, Albert S. Lee, Seung-Hyub Baek, Heesuk Kim, Tae Joo Park, Jin-Sang Kim, Seong Keun Kim
Summary: This study demonstrates the use of atomic layer deposition (ALD) to create a thin Al2O3 layer on n-type Bi2Te2.7Se0.3, which helps improve their thermoelectric performance by reducing the adverse effects of multiple boundaries. The ALD cycle effectively suppresses volatilization and reduces the electron concentration while inducing numerous boundaries to decrease thermal conductivity. However, increasing the number of ALD cycles leads to a rise in resistance and degradation of performance. Overall, the ZT value is increased by 51% with a single ALD cycle.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
Article
Nanoscience & Nanotechnology
Min Gye Kim, Nam-Kwang Cho, Jin Hyun Ma, Min Ho Park, Jeong Hyeon Park, Woojin Jeon, Seong Jun Kang
Summary: We have developed a promising deposition method for fabricating controllable layer-by-layer (LbL) quantum-dot (QD) structures. By utilizing a spray coating method, we were able to induce desired properties of QD thin films and control the thickness of QD layers. The application of an intermediate heat treatment between spray pass cycles successfully prevented cluster formation on the spray-coated QD films, resulting in the LbL structure of Sr-QDs with fewer surface defects and improved crystallinity, ultimately leading to enhanced performance of optoelectronic devices.
ACS APPLIED NANO MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Jeong Hyeon Park, Ye Won Kim, Myeong Ho Kim, Jin-Sik Kim, Woojin Jeon
Summary: In this study, we developed a Mometal thin film deposition process using two steps: Mo2N thin film deposition through plasma-enhanced atomic layer deposition, followed by rapid thermal annealing. The mechanism of Mo2N reduction during post-deposition annealing was investigated. Agglomeration during the reduction process was successfully prevented by employing a hydrogen-permeable mechanical capping layer. Eventually, a low-resistance Mo thin film formation process was achieved, even at a thickness of 5 nm.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Jun Hyung Jeong, Min Ho Park, Hanseok Jeong, Wonsik Kim, Soohyung Park, Woojin Jeon, Seong Jun Kang
Summary: Inspired by the human visual system, optoelectronic synaptic transistors have gained attention as promising candidates for next-generation neuromorphic computing systems. In order to achieve low-cost, mass production, devices need to be fabricated through a solution process. Researchers have successfully improved the photoresponse characteristics and electrical characteristics of optoelectronic synaptic transistors by introducing an indium gallium zinc oxide-based transistor doped with cadmium.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Ae Jin Lee, Seungwoo Lee, Dong Hee Han, Youngjin Kim, Woojin Jeon
Summary: In this study, the discrete feeding method (DFM) in atomic layer deposition (ALD) was used to prevent interfacial layer formation between electrodes and insulators. The results showed that DFM significantly improved precursors' chemisorption efficiency, growth rate, and reduced deposition time in ALD. By applying DFM to the deposition of ZrO2, interfacial layer formation was prevented. These findings provide new insights into interfacial layer formation and have implications for the development of electronic devices.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Materials Science, Multidisciplinary
Ye Won Kim, Ae Jin Lee, Dong Hee Han, Dae Cheol Lee, Ji Hyeon Hwang, Youngjin Kim, Songyi Moon, Taewon Youn, Minyung Lee, Woojin Jeon
Summary: In this study, an atomic layer deposition (ALD) process was developed to produce highly crystalline and high work function MoO2 thin films. The mechanism of stabilizing and crystallizing the metastable MoO2 phase by the template effect was revealed. The template effect not only controlled the crystallinity but also the stoichiometry of the deposited thin film. A rutile TiO2 thin film with a high dielectric constant of 150 was obtained by employing MoO2.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Materials Science, Multidisciplinary
Min Gye Kim, Jae Seung Shin, Jin Hyun Ma, Jun Hyung Jeong, Dong Hee Han, Beom-Su Kim, Woojin Jeon, Yongsup Park, Seong Jun Kang
Summary: This paper presents the use of an Al-doped TiO2 (ATO) interfacial layer to improve the charge balance in QLEDs, resulting in enhanced luminance and efficiency. The study demonstrates that a better interfacial energy level alignment can be achieved by increasing the number of oxygen vacancies and titanium defect sites. With the optimized ATO interfacial layer, QLEDs exhibit improved luminance, current efficiency, and device lifetime.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
