Micro and Nanostructures最新文献

{"title":"Fabrication and simulation of optical shaping diffuser to control light patterns","authors":"Po-Wei Chiu ,&nbsp;Tien-Li Chang ,&nbsp;Wei-Chun Chen ,&nbsp;Yeeu-Chang Lee","doi":"10.1016/j.micrna.2024.208030","DOIUrl":"10.1016/j.micrna.2024.208030","url":null,"abstract":"<div><div>This study utilizes a 532 nm ps laser micromachining technique on Schott-B270 glass to fabricate micro-lens array (MLA) with optimized curvature and minimal surface roughness, aimed at achieving an optical shaping diffuser. The research demonstrates a two-step fabrication process that combines picosecond laser processing with wet etching, significantly enhancing optical diffusion. Square-shaped micro-lenses with diffusion angles ranging from 29° to 62° were successfully created, along with hexagonal and rectangular shapes. Optical simulations using LightTools, which employed built-in Bezier curves to design micro-lens parameters, analyzed the impact of micro-lens arrangements on light patterns. The simulations indicated that varying the spacing and overlap ratio of the micro-lenses influenced light intensity distribution, achieving uniform light patterns with intensity variations of less than 10 %. Experimental validation through optical measurements confirmed that the fabricated MLA produced well-defined light patterns, demonstrating their effectiveness for various optical applications. This work contributes to advancing the understanding of micro-lens fabrication techniques and their applications in enhancing light distribution.</div></div>","PeriodicalId":100923,"journal":{"name":"Micro and Nanostructures","volume":"198 ","pages":"Article 208030"},"PeriodicalIF":2.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dual doped ring reconfigurable FET and its process variation analysis using random forest algorithm","authors":"Indira Chatterjee,&nbsp;Srinivasan R","doi":"10.1016/j.micrna.2024.208056","DOIUrl":"10.1016/j.micrna.2024.208056","url":null,"abstract":"<div><div>This work combines three concepts, (i) reconfigurability, (ii) dual doped source-drain, and (iii) Ring FET to propose dual doped ring reconfigurable FET (D²R²FET). The proposed device concept has been demonstrated through DC and AC numerical device simulations. Its performance has been optimized by adjusting the source radius. Additionally, the device has also been studied for process variation impact using random forest algorithm. We have the following findings from the above studies, (i) source at the centre of structure offers better drive current compared to the drain at the centre structure, and (ii) Proposed device offers AC performance (unity gain cut-off frequency of 554Hz). Apart from these, the process variation study finds out the channel height (or epi-layer) and control gate work function as the most significant parameters.</div></div>","PeriodicalId":100923,"journal":{"name":"Micro and Nanostructures","volume":"198 ","pages":"Article 208056"},"PeriodicalIF":2.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pharmaceutical emerging pollutants photodegradation by the action of g-C3N4/BiVO4 heterojunctions","authors":"E. Luevano-Hipolito,&nbsp;D. Sánchez-Martínez,&nbsp;I. Juarez-Ramírez","doi":"10.1016/j.micrna.2024.208053","DOIUrl":"10.1016/j.micrna.2024.208053","url":null,"abstract":"<div><div>Emerging contaminants are increasingly common in natural resources causing adverse health effects on humans, animals, and the environment. Thus, recently, a significant need for research to develop sustainable purification approaches to remove these pollutants from wastewater plants is required. Heterogenous photocatalysis represents a promising approach to remove traces of these pollutants from wastewater using semiconductor oxides. Some of the most promising materials for this purpose are g-C₃N₄ and BiVO₄, which when combined in a heterojunction favor high efficiencies to remove water trace pollutants, e.g., pharmaceuticals. Therefore, this work proposes the optimization of the synthesis of the g-C₃N₄/BiVO₄ heterojunction by microwave-hydrothermal method (MW-H) with an orthogonal L₉ Taguchi design of experiments. During the synthesis, four factors were changed: load of BiVO₄, power, temperature, and time of the MW-H method, to find the optimal conditions to obtain g-C₃N₄/BiVO₄ heterojunctions with outstanding efficiencies to remove trace drugs of acetaminophen and tetracycline, contributing to proposes solutions for water purification. The g-C₃N₄/BiVO₄ heterojunction promoted efficiencies to remove both drugs up to 74 % for acetaminophen and 87 % for tetracycline, confirming mineralization degree of 21 and 35 %, respectively. A mechanism for the decomposition of the organic molecules was proposed through the study of oxidant species.</div></div>","PeriodicalId":100923,"journal":{"name":"Micro and Nanostructures","volume":"198 ","pages":"Article 208053"},"PeriodicalIF":2.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to ‘Innovative spacer material integration in tree-FETs for enhanced performance across variable channel lengths’ [Micro Nanostruct. 195 207974 (2024)]","authors":"Dharavath Parvathi,&nbsp;P. Prithvi","doi":"10.1016/j.micrna.2024.208046","DOIUrl":"10.1016/j.micrna.2024.208046","url":null,"abstract":"","PeriodicalId":100923,"journal":{"name":"Micro and Nanostructures","volume":"198 ","pages":"Article 208046"},"PeriodicalIF":2.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiple-parameter optimization of AlGaN nanoarrays based on optical absorption accelerated by machine learning","authors":"Xian Wu ,&nbsp;Hongkai Shi ,&nbsp;Yuyan Wang ,&nbsp;Yuting Dai ,&nbsp;Chaoling Du ,&nbsp;Yu Diao ,&nbsp;Sihao Xia","doi":"10.1016/j.micrna.2024.208061","DOIUrl":"10.1016/j.micrna.2024.208061","url":null,"abstract":"<div><div>AlGaN nanorod arrays (NRAs) have considerable significance in optoelectronic devices. However, due to the specificities of their structure, it is imperative to address the global optimization of material parameters, geometrical parameters, and system parameters. In this study, a combination of COMSOL simulation and machine learning is utilized to investigate the absorption under global parameter adjustment. Firstly, the optical absorptivity of Al_0.35Ga_0.65N modified by a single parameter is simulated and analyzed. The absorption of NRAs exceeds that of thin films. Moreover, the absorption is notably enhanced under forward incidence (FI) of photons compared to reverse incidence (RI). The optimal parameters for NRAs under FI are a diameter of 250 nm, a height of 600 nm, a substrate thickness of 50 nm, and an arrays period of 250 nm. Using the simulated results as dataset for machine learning, three regression forecasting models (RFR, DTR and NNR) are adopted. These models are meticulously trained and subsequently utilized to predict the absorption. The results indicate that RFR owns the highest accuracy with R² of 0.97 and MAE of 3.66. The validation set is additionally employed to verify the accuracy of RFR with 96 % area within the differential heatmap closed to zero. This research is expected to offer valuable insights for the structural design and optimization methods of AlGaN NRAs in the application of photocathodes, solar cells and photodetectors.</div></div>","PeriodicalId":100923,"journal":{"name":"Micro and Nanostructures","volume":"198 ","pages":"Article 208061"},"PeriodicalIF":2.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elimination of band-edge states by Frenkel-like defects: Application in inorganic compound α-Ag2S","authors":"Shuang Qiu ,&nbsp;Hanyang Ji ,&nbsp;Kaixuan Jin ,&nbsp;Shuhan Tang ,&nbsp;Xiaojie Liu","doi":"10.1016/j.micrna.2025.208085","DOIUrl":"10.1016/j.micrna.2025.208085","url":null,"abstract":"<div><div>The elimination of impurity states is an effective method to improve the properties of semiconductor material. Interstitial Se or Te doping in inorganic compound α-Ag₂S would induce highly localized impurity states around the valence band maximum (VBM), which are so-called perturbed host states (PHSs). These PHSs possibly act as the recombination center and would affect the carrier transport. Herein, we propose the self-compensation method to eliminate the PHSs by introducing Frenkel-like defects. The first-principles calculations prove that the Frenkel-like defects, i.e., one first-nearest neighbor S-vacancy (V_1S) around the interstitial dopant (Se_i + V_1S or Te_i + V_1S), are able to eliminate the PHSs. The Frenkel-like defect can not only achieve compensation for electronic structure, but also achieve compensation for carrier concentration. Instead, excessive Schottky defects would lead to partial compensation or overcompensation. Additionally, it is also found that the existence of Frenkel-like defect can lower the formation energy and improve the stability of the system. This discovery highlights the importance of Frenkel-like defects in eliminating impurity states, which is fundamentally different from the traditional scheme that mainly credits no introduction of additional foreign elements. Our results provide a new avenue to the design of eliminating impurity states in other semiconductors.</div></div>","PeriodicalId":100923,"journal":{"name":"Micro and Nanostructures","volume":"200 ","pages":"Article 208085"},"PeriodicalIF":2.7,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143168532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultra-wide range infrared photodetector based on BP/MoSe2 heterojunction","authors":"Beiyun Liu ,&nbsp;Chengjie Zhi ,&nbsp;Guanxia Dai ,&nbsp;Boxing An ,&nbsp;Feihong Chu ,&nbsp;Jicheng Mo ,&nbsp;Xiuyan Zhang","doi":"10.1016/j.micrna.2025.208081","DOIUrl":"10.1016/j.micrna.2025.208081","url":null,"abstract":"<div><div>Two-dimensional (2D) materials based photodetectors is a hot research field in recent years, especially black phosphorus (BP), which has been favored by researchers due to its benign properties of direct bandgap and bandgap of only 0.3 eV. However, devices based on BP only have low photoresponsivity and the material is prone to degradation, which is not conducive to their research in photodetectors. We constructed a BP and molybdenum molybdenum diselenide (MoSe₂) heterojunction photodetector by depositing electrodes and then transferring materials using a dry transfer method. A pn junction is formed by p-type BP and n-type MoSe₂, which generates a built-in electric field that helps to separate the photogenerated electron-hole pairs and improve the efficiency of photo detection. The device has a maximum photoresponsivity and specific detectivity of 0.167 A/W and 1.2 × 10¹⁰ Jones at V_ds = 1 V, V_g = 0 V. The range of photo detection can be from 450 to 2400 nm. Our work has a positive impact on the research of two-dimensional material heterojunctions for infrared photodetectors.</div></div>","PeriodicalId":100923,"journal":{"name":"Micro and Nanostructures","volume":"199 ","pages":"Article 208081"},"PeriodicalIF":2.7,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive evaluation of T-gated AlN/GaN/SiC MOSHEMTs with ZrO2/Al2O3 dielectrics towards performance enhancement through lateral scaling and passivation optimization for power switching and RF applications","authors":"Lavanya Repaka,&nbsp;J. Ajayan,&nbsp;Sandip Bhattacharya,&nbsp;B. Mounika","doi":"10.1016/j.micrna.2025.208080","DOIUrl":"10.1016/j.micrna.2025.208080","url":null,"abstract":"<div><div>At the nanoscale regime, achieving substantial RF performance in GaN-based MOSHEMTs requires a high aspect ratio, which is particularly crucial in AlN/GaN MOSHEMTs due to the thin AlN barrier layer. This study compares the performance of AlN/GaN MOSHEMTs using two dielectric materials, ZrO₂ and Al₂O₃. The analysis systematically examines the effects of varying barrier thickness (t_b), oxide thickness (t_ox), and gate length (L_G) to optimize device characteristics. As t_b and t_ox are reduced, both dielectrics exhibit an increase in gate capacitance (C_GG) due to reduced separation between the gate and channel, which enhances gate control and improves device performance. Furthermore, L_G scaling reveals that at 40 nm, both devices exhibit enhanced performance due to stronger electric fields and increased carrier velocity enabled by reduced channel length. From the comprehensive analysis, it is observed that ZrO₂ consistently surpasses Al₂O₃ in terms of key performance metrics across varying structural parameters. Notably, the ZrO₂ device outperforms the Al₂O₃ counterpart achieving peak values of 2.4 A/mm (I_D), 536.8 mS/mm (G_M), and f_T of 300.5 GHz with an L_G of 40 nm. This superior performance is attributable to the higher dielectric constant of ZrO₂, which enables greater physical thickness, effective gate control, better interface quality, and enhanced transport properties due to the shorter gate length. Besides, we investigated the impact of passivation materials, using SiO₂, Al₂O₃, and Si₃N₄, and found that SiO₂ provides superior performance owing to efficient reduction in surface states. Additionally, the effects of passivation thickness on device performance were examined using SiO₂, revealing that increased passivation thickness leads to improved overall electrical characteristics with peak values of 2.45 A/mm (I_D), 552.28 mS/mm (G_M), and f_T of 409.54 GHz, due to a reduction of surface traps and suppressed leakage currents. The study demonstrates the superior performance and compatibility of ZrO₂ under various scaling conditions, establishing it as a highly intriguing gate dielectric material for GaN HEMTs, particularly in sub-50 nm regimes. These findings underscore the potential of ZrO₂ for optimized RF performance in scaled AlN/GaN MOSHEMTs for future RF &amp; power-switching applications.</div></div>","PeriodicalId":100923,"journal":{"name":"Micro and Nanostructures","volume":"199 ","pages":"Article 208080"},"PeriodicalIF":2.7,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Over 20 % improvement of current-gain cut off frequency 0.3 μm AlGaN/GaN HEMTs with ultra-low Von Schottky Drain for broadband application","authors":"Zhe Lin ,&nbsp;Jihong Ding ,&nbsp;Hanzhao He ,&nbsp;Dongsheng Liu ,&nbsp;Wei Huang ,&nbsp;Liang Li ,&nbsp;D.W. Zhang ,&nbsp;Hao Yu ,&nbsp;Xubo Song ,&nbsp;Yuanjie Lv ,&nbsp;Zhihong Feng ,&nbsp;Baitong Fang ,&nbsp;Kai Zhang ,&nbsp;Debin Zhang","doi":"10.1016/j.micrna.2025.208076","DOIUrl":"10.1016/j.micrna.2025.208076","url":null,"abstract":"<div><div>This letter demonstrates firstly the novel IESD HEMT (Inserting Etched Schottky Drain HEMT) with the lower barrier height for the broadband and high temperature application of millimeter wave. The etched Schottky device is formed adjacent along AlGaN/GaN sidewalls into drain region and the turn-on voltage is almost about 0 V with the barrier height about 0.49 eV, 0.02 eV lower than that of conventional AlGaN/GaN SBD (Schottky Barrier Diode). Due to the hot electron emission effect of the inserted Schottky barrier diode, the results show that the HEMTs device can obtain better electrical characteristics with wide bandwidth in wider temperature range from 25 °C to 125 °C, specially improved on high frequency. The fabricated HEMTs show a high current density of 550 mA/mm and a high transconductance of 168 mS/mm (V_DS = 10V). Based on the nonlinear rectifying characteristics of SBD with containing RF harmonic components, the cut-off frequency <em>f</em>_T of IESD HEMT exceeds 75.7 GHz which is about 20 % higher than conventional AlGaN/GaN HEMT devices.</div></div>","PeriodicalId":100923,"journal":{"name":"Micro and Nanostructures","volume":"199 ","pages":"Article 208076"},"PeriodicalIF":2.7,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Porous nanosheets-assembled NiMoO4–NiO microflowers for high-selectivity to NO2","authors":"Haibo Ren ,&nbsp;Hui Pan ,&nbsp;Gaoju Zhang ,&nbsp;Jiarui Huang","doi":"10.1016/j.micrna.2025.208079","DOIUrl":"10.1016/j.micrna.2025.208079","url":null,"abstract":"<div><div>This study synthesized a porous structure of NiMoO₄–NiO microflowers assembled with uniform nanosheets using a facile hydrothermal technique and calcination method. The unique porous microflower, consisting of the nanosheets assembled together, provides abundant space for gas diffusion and channels for electron transport. The gas sensor, fabricated using the NiMoO₄–NiO microflowers, exhibited outstanding sensing behaviors towards NO₂ gas. It showed a higher response value of 36.9 at 210 °C, with short response/recovery times of 30 s/16 s for 100 ppm NO₂ gas. The detection limit for NO₂ gas was 207 ppb. Additionally, it demonstrated high selectivity to NO₂ gas and excellent long-term stability. Furthermore, the sensor was tested under different relative humidity conditions. The superior NO₂ sensing properties are attributed to the abundant p-p heterojunctions, synergistic catalytic effect between the NiMoO₄ and the NiO, and the porous microflowers. The NiMoO₄–NiO microflowers sensor shows great promise for detecting NO₂ gas in practical applications.</div></div>","PeriodicalId":100923,"journal":{"name":"Micro and Nanostructures","volume":"199 ","pages":"Article 208079"},"PeriodicalIF":2.7,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}