Article
Physics, Applied
T. Tajiri, M. Yoshida, S. Sosumi, K. Shimoyoshi, K. Uchida
Summary: GaN 2D photonic crystal nanocavities with a single embedded InGaN quantum well were fabricated using photo-electrochemical etching. The resonant modes of the photonic crystal nanocavities were investigated using micro-photoluminescence spectroscopy. The measured resonant peaks and their dependence on the photonic crystal period were in good agreement with numerical analysis, allowing for the determination of the fundamental mode. The highest quality factor for the fundamental mode reached 3400 at blue wavelengths. This work is important for the improvement of GaN 2D photonic crystal nanocavities and their applications in integrated light sources in visible wavelengths.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Clint D. Frye, Scott B. Donald, Catherine E. Reinhardt, Rebecca J. Nikolic, Lars F. Voss, Sara E. Harrison
Summary: The study demonstrates that SiO2 can serve as an effective mask material for deep etching of GaN devices with high selectivity, achieving GaN:SiO2 selectivities greater than those reported for metal hard masks. Introducing Al and AlCl into the plasma enables ultrahigh SiO2 selectivities, providing a low-contamination pathway for etching deep GaN microdevices.
MATERIALS RESEARCH LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Chang-Hsun Huang, Chia-Yi Wu, Yen-Fu Lin, Yi-Chia Chou, Ko-Tao Lee
Summary: By utilizing wet etching, nanowire-based memristors using nitride materials have been developed and shown advantages of low power consumption and high integrated memristive capabilities, which have promising applications in bio-inspired artificial synapses.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Physics, Applied
T. Tajiri, S. Sosumi, K. Shimoyoshi, K. Uchida
Summary: GaN micro-disk cavities are fabricated using laser-assisted photo-electrochemical (PEC) etching and optically characterized. The laser source used in PEC etching selectively etches the InGaN/GaN superlattice beneath the GaN disk. Whispering gallery modes (WGMs) in fabricated GaN micro-disk cavities are evaluated using micro-photoluminescence spectroscopy. The results show high-Q WGMs at blue-violet wavelengths, indicating the potential of laser-assisted PEC etching in fabricating air-clad GaN micro-cavities.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Sabria Benrabah, Maxime Legallais, Pascal Besson, Simon Ruel, Laura Vauche, Bernard Pelissier, Chloe Thieuleux, Bassem Salem, Matthew Charles
Summary: This study explores the impact of several wet etchants commonly encountered in the microelectronic industry on the surface chemistry of GaN on silicon. Phosphoric acid treatment is found to significantly modify the surface and enable the recovery of the surface morphology. The study proposes a promising treatment method for the recovery of good quality GaN surfaces after dry etching.
APPLIED SURFACE SCIENCE
(2022)
Article
Physics, Applied
Yasuhisa Sano, Genta Nakaue, Daisetsu Toh, Jumpei Yamada, Kazuto Yamauchi
Summary: This study investigates the use of hydrogen radicals instead of chlorine radicals in atmospheric-pressure plasma etching of a gallium nitride (GaN) substrate. This method aims to reduce the on-resistance of GaN vertical power devices by thinning the backside. By placing a pipe-shaped electrode in front of the GaN substrate, atmospheric-pressure plasma was generated using a mixture of helium and hydrogen gas, achieving a high-speed etching rate of about 4 μm/min. Although spherical Ga metal particles were observed on the surface after processing, the addition of oxygen gas was found to suppress their formation.
APPLIED PHYSICS EXPRESS
(2023)
Article
Nanoscience & Nanotechnology
Yikai Liao, You Jin Kim, Junyu Lai, Jung-Hun Seo, Munho Kim
Summary: Metal-assisted chemical etching (MacEtch) can create GaN nanoridge surfaces on undoped GaN thin films, reducing surface reflection in the UV regime and enhancing photodiode responsivity by 6 times.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Engineering, Electrical & Electronic
Clint D. Frye, Catherine E. Reinhardt, Scott B. Donald, Lars F. Voss, Sara E. Harrison
Summary: This study investigates the effects of substrate temperature, RF power, and ICP power on GaN micropillar sidewall roughness and etch characteristics. The results show that adjusting these parameters can improve the sidewall etch morphology and produce extremely smooth surfaces suitable for GaN regrowth and new device structures.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
S. N. Sohimee, Z. Hassan, W. F. Lim, N. M. Ahmed, R. Radzali
Summary: The theoretical and experimental study of porous p-type gallium nitride (GaN) is discussed in this work. Porous p-type GaN was fabricated using an alternating current photo-assisted electrochemical etching technique and its morphology and structural properties were characterized. The results show that etching time has a significant impact on the morphology and structural properties of porous p-type GaN.
INTERNATIONAL JOURNAL OF NANOTECHNOLOGY
(2022)
Article
Physics, Applied
Tianhao Jiang, Jian Wang, Jiaqi Liu, Meixin Feng, Shumeng Yan, Wen Chen, Qian Sun, Hui Yang
Summary: Semiconductor nano-membranes offer a new approach to improve the performance of optical devices. In this study, we present a fabrication method for GaN-based LED membranes, which includes the complete device structure including contact metals from Si substrate. The method involves electrochemical etching of the highly conductive AlN/Si interface, which is naturally formed in GaN-on-Si materials. Photoluminescence and Raman scattering spectra show reduced internal stress, and electrical measurements demonstrate decreased leakage current and series resistance, indicating the successful preservation of the whole structure.
APPLIED PHYSICS EXPRESS
(2022)
Article
Chemistry, Physical
Tomas Ceponis, Jevgenij Pavlov, Arunas Kadys, Augustas Vaitkevicius, Eugenijus Gaubas
Summary: Using wet etching method can improve the photoluminescence efficiency of MOCVD GaN materials and a blue luminescence band related to dislocations was discovered. The intensity of the blue luminescence band increases with longer wet etching exposure. The mechanisms of scintillation intensity and spectrum variations were examined through complementary photo-ionization and photoluminescence spectroscopy techniques, and the dislocation etch pits were analyzed by scanning techniques.
Article
Optics
Yan Ou, Changyou Li, Jinwen Qian, Yifeng Xiao, Sheng Li, Zhengqiang Feng
Summary: This paper demonstrates the formation of hexagonal microstructures on GaN films via femtosecond laser ablation and wet chemical etching, and shows that the structures can be tuned by adjusting the laser energy and etching time.
OPTICS COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Prudhvi Peri, Kai Fu, Houqiang Fu, Yuji Zhao, David J. Smith
Summary: The effects of etching treatment on GaN-on-GaN structures for power device applications were investigated in this study. It was found that optimizing surface etching techniques is important to avoid degraded performance in devices that require regrowth of GaN. Devices with fast-etch-only treatment showed lower breakdown voltages compared to those with multiple etching steps, where no interfaces were visible and the breakdown voltages were significantly higher.
JOURNAL OF ELECTRONIC MATERIALS
(2021)
Article
Engineering, Electrical & Electronic
Pao-Chuan Shih, Girish Rughoobur, Kai Cheng, Akintunde Akinwande, Tomas Palacios
Summary: Field emitters have attracted much attention for high-frequency and harsh-environment applications, with III-Nitrides showing promise due to their tunable electron affinities. The main challenges for low turn-on-voltage III-Nitrides field emitters are the lack of a self-aligned gate and tip-sharpening technologies. This study demonstrates self-aligned-gated GaN field emitter arrays with sharpened tips using wet-based digital etching technology.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Y. Chen, Y. Xing, J. T. Gong, Qi Li, X. Guo
Summary: This paper investigates the wet etching rate distribution of GaN < 0001 > crystal zone in H3PO4 etchant with different temperatures and concentrations using wagon-wheel structures fabricated on GaN (0 0 0 1) substrate. The results show that GaN exhibits six-fold symmetrical anisotropy about the c-axis in the < 0001 > crystallographic zone, and H3PO4 etching results in lower surface roughness and etch rate fluctuation compared to AZ400K etching. The apparent activation energy and the dependence of etch rate on concentration are also analyzed in this study. The step flow theory is successfully applied to explain the etching rate anisotropy at the atomic scale.
SENSORS AND ACTUATORS A-PHYSICAL
(2023)
Article
Chemistry, Analytical
Natheer A. Algadri, Ahmad M. AL-Diabat, Naser M. Ahmed
Summary: The chemical spray pyrolysis technique was used to synthesize zinc sulfide thin films without annealing treatment. The ZnS films showed distinct characteristics with different Zn:S ratios, and exhibited a strong response to UV illumination when used in MSM photodetectors.
INSTRUMENTATION SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Aminu Muhammad, Sabah M. Mohammad, Zainuriah Hassan, Suvindraj Rajamanickam, Shireen Mohammed Abed, M. G. B. Ashiq
Summary: The purpose of this study is to enhance the electrical and optical properties of zinc oxide (ZnO) by doping it with silver (Ag) and fluorine (F). F and Ag co-doped ZnO nanorods were synthesized using a modified hydrothermal method, and an ultraviolet metal-semiconductor-metal photodetector (PD) was fabricated. The results showed that the co-doped sample had improved crystal quality, reduced defect density, decreased bandgap, and enhanced sensitivity and response times of the PD.
MICROELECTRONICS INTERNATIONAL
(2023)
Article
Engineering, Electrical & Electronic
Shireen Mohammed Abed, Sabah M. Mohammad, Zainuriah Hassan, Aminu Muhammad, Suvindraj Rajamanickam
Summary: This study fabricated a UV metal-semiconductor-metal (MSM) photodetector based on zinc oxide nanorods (ZnO NRs) grown on seeded silicon substrate using a low-cost drop-casting technique. The performance of the fabricated MSM devices was investigated and discussed. The fabricated ZnO NRs UV photodetector showed high stability, photocurrent, sensitivity, and responsivity under 365 nm wavelength illumination and various applied bias.
MICROELECTRONICS INTERNATIONAL
(2023)
Article
Chemistry, Multidisciplinary
S. A. Abdulateef, Muna E. Raypah, A. F. Omar, M. Z. Mat Jafri, Naser M. Ahmed, Noor Haida Mohd Kaus, Azman Seeni, Mohd Hafiz Mail, Yasser Tabana, Marawan Ahmed, Sara Al Rawashdah, Khaled Barakat
Summary: This study successfully synthesized gold nanoparticles using pulsed laser ablation technique and explored the effects of bovine serum albumin on particle stability and aggregation. The synthesized nanoparticles showed low toxicity and high biocompatibility, making them promising for therapeutic applications.
ARABIAN JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Physical
Lary H. Slewa, Fayroz A. Sabah, Bestoon A. Gozeh, Hazha Omar Othman, Tariq A. Abbas, Naser M. Ahmed
Summary: A heterostructure of (Au-NPs/MacroPSi) was synthesized to enhance the performance of MacroPSi as a pH-EGFET sensor. The results showed that the heterostructure exhibited high pH sensitivity, linearity, and hysteresis, as well as rapid acid and base response.
Article
Chemistry, Multidisciplinary
Anas A. M. Alqanoo, Naser M. Ahmed, Md. R. Hashim, Munirah A. Almessiere, Sofyan A. Taya, Ahmed Alsadig, Osamah A. Aldaghri, Khalid Hassan Ibnaouf
Summary: The applications of silver nanowires (AgNWs) depend on their purity and morphology. In this study, the morphological changes of AgNWs during growth were tracked to determine the optimal reaction time and temperature. UV-Vis absorption spectra were used to investigate the relationship between reaction time and temperature. An equation was developed to calculate reaction time at any given reaction temperature. The average diameter of the AgNWs was found to be temperature-dependent, with the minimum value observed at a reaction temperature of 150°C. A purification technique was conducted to remove by-products, and an AgNWs-based porous Si device was fabricated and showed high sensitivity and detectivity.
Article
Materials Science, Multidisciplinary
Anas A. M. Alqanoo, Naser M. Ahmed, Md Roslan Hashim, Ahmed Alsadig, Shahad Al-Yousif, Sofyan A. Taya, Osamah A. Aldaghri, Khalid Hassan Ibnaouf
Summary: In this study, a 3D network of silver nanowires (AgNWs) was successfully synthesized and characterized. Polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) were used as the reductant and structure-directing agent, respectively. The AgNW-based heater with a wood substrate showed the shortest response time, highest thermal resistance, and stable temperature at a low bias voltage.
Article
Materials Science, Multidisciplinary
M. Z. Mohd Yusoff, A. Mahyuddin, Z. Hassan, M. S. Yahya
Summary: The study investigates the influence of high thermal annealing on the surface morphological, structural, and optical properties of ZnO/AlN/GaN/AlN layers grown on Si substrate by MBE. ZnO thin film was deposited on AlN/GaN/AlN heterostructures using RF sputtering machine. Thermal annealing at different temperatures (600 degrees C and 800 degrees C) with nitrogen flow was applied to the samples in a vacuum tube furnace. Surface morphological, structural, and optical properties were characterized using FESEM, AFM, HR-XRD, and Raman spectroscopy. The optimal thermal annealing temperature was found to be 600 degrees C, resulting in the lowest dislocation density in the films based on the optical and structural evaluation.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2023)
Article
Physics, Applied
Muna E. Raypah, Naser M. Ahmed, Naif H. Al-Hardan, Munirah A. Almessiere
Summary: In this study, a novel seedless and surfactant-free CBD method at low temperature was used to fabricate flower-shaped ZnO nanostructures (FZONSs) on glass and p-type silicon substrates for the first time. The structural properties of FZONSs were examined and showed three-dimensional flower-shaped nanomorphology. The grown FZONSs may have potential in various applications including advanced catalysts, sensing devices, and solar cells.
INTERNATIONAL JOURNAL OF MODERN PHYSICS B
(2023)
Article
Chemistry, Physical
A. K. Tan, N. A. Hamzah, M. A. Ahmad, S. S. Ng, Z. Hassan
Summary: In this study, InGaN/GaN heterostructures were grown on a flat sapphire substrate using MOCVD technique. Results showed that a higher V/III ratio led to parasitic behavior by hydrogen dissociated from ammonia, which etched the InN and changed the growth morphology. Moreover, the InGaN thin films grown at higher V/III ratios exhibited more stable bandgap energy and improved electrical properties. The correlation between strain and carrier density was also discussed, and it was concluded that high-quality and thick InGaN thin films could be grown for solar cell applications at higher V/III ratio conditions.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Han Yann Heng, Muhamad Fikri Zaini, Leong Wei Xian Rebecca, Muhammad Aizat Abu Bakar, Mohamad Shuaib Mohamed Saheed, Abdul Razak Ibrahim, Naser Mahmoud Ahmed, Mundzir Abdullah
Summary: There is an urgent need to remove toxic lead from popular halide perovskite used in photonics and optoelectronics. This study demonstrates the synthesis of lead-free halide perovskite using an eco-friendly solvent and characterizes its properties. It also investigates the optical and nonlinear optical properties. This green and facile synthesis approach provides an alternative for the new applications of Bi-based perovskite.
PHOTONICS AND NANOSTRUCTURES-FUNDAMENTALS AND APPLICATIONS
(2023)
Proceedings Paper
Polymer Science
Alaa Falih Ismael, Naser M. Ahmed, Khalid H. Ibrahim, Ahmed A. AL-Kubaisi
Summary: Synthesis of metallic nanoparticles using tea plant leaves is a recognized and non-toxic method that offers reduced environmental impact and the potential for large-scale production. The use of plant extracts as both reducing and stabilizing agents allows for better control of shape and size, enabling various applications.
MACROMOLECULAR SYMPOSIA
(2023)
Article
Materials Science, Ceramics
Munirah Jamil, Iskandar Shahrim Mustafa, Naser Mahmoud Ahmed, Shahrul Bariyah Sahul Hamid, Thair Hussien Khazaalah, Efenji Godwin, Nabasu Seth Ezra, Hayder Naeem Salah
Summary: Novel magnetic resonance imaging (MRI) diagnostic nanofibres were synthesized by embedding Er2O3 nanoparticles (2% to 8%) in the PEO matrix using electrospinning. The resulting PEO/Er2O3 nanofibres were characterized and evaluated for their magnetic relaxivity in MRI contrast enhancement. The addition of Er2O3 nanoparticles led to changes in the conformational structure and crystalline properties of the nanofibres, demonstrating potential T2 and T1-T2 dual-mode diagnostic capabilities in MRI 1.5T.
CERAMICS INTERNATIONAL
(2023)
Article
Optics
Ali Saleh Alkadem Idriss, Nik Noor Ashikin Nik Ab Razak, Naser M. Ahmed, Youssef Aboubaker Abdulla
Summary: A novel TiO2/Cu/TiO2 multilayer thin film dosimeter with faster deposition rate, high purity, and uniformity was fabricated. The film has an amorphous, porous structure with spherical nanoparticles and is transparent in the visible region. The optimum TL intensity was found with the TiO2 (445 nm) / 14.2 nm Cu / TiO2 (130 nm) sequence. The multilayer film is suitable for thermoluminescence dosimetric applications.
JOURNAL OF LUMINESCENCE
(2023)
Review
Chemistry, Physical
Marwa Jawad Kadhim, Mazin Auny Mahdi, Abbas Mohammed Selman, Salwan Kamal Jamel Al-Ani, Jalal Jabar Hassan, Naser Mohammed Ahmed
Summary: Organic dyes are a major source of water pollution, causing serious health problems for living organisms. The removal of dye pollution is crucial due to its high toxicity, leading to increased interest from researchers. Heterogeneous photocatalysis based on ZnO is an important method for pollution treatment, and this review focuses on the use of ZnO nanostructure and modified ZnO as photocatalysts, discussing the mechanisms and factors influencing the photocatalytic process.
IRANIAN JOURNAL OF CATALYSIS
(2023)
