Pub Date : 2024-09-12DOI: 10.1088/1361-6641/ad7637
Hongbo Li, Jian Zhang, Chongyong Guo, Yuanya Liu, Chunyan Liu, Yu Wang, Jianjun Li, Hui Yuan and Xingcheng Jin
Hf0.5Zr0.5O2 (HZO), an innovative and exceptional ferroelectric material, exhibits remarkably high sensitivity, making it particularly vulnerable to electrode effect. Titanium nitride (TiN) is a commonly employed as electrode material in the complementary metal–oxide–semiconductor process. Optimizing the process parameters of preparing TiN film can alter matching degree with HZO capacitor, so as to find the optimal parameters of TiN process to improve ferroelectric property of HZO. In this study, the impact of key process parameters in atomic layer deposition (ALD) TiN, including cycle number, TiCl4 and NH3 pulse time, process temperature (Tp) on film thickness, crystalline phases of TiN, square resistivity (Rs), surface average roughness (Ra) and the root-mean-square roughness (Rq) of TiN film are comprehensively investigated. Through optimization, ∼10 nm ALD TiN film can achieve excellent uniformity of 0.43%, low Rs of 286.9 Ω/□, improved Ra and Rq of 1.82 Å and 2.28 Å. The results show that the maximum 2 times remnant polarization (2Pr) of the HZO ferroelectric capacitor with optimized TiN electrodes can reach 35.17 µC cm−2, and the switching cycle endurance exceeds 8 × 107.
Hf0.5Zr0.5O2 (HZO) 是一种创新的特殊铁电材料，具有极高的灵敏度，因此特别容易受到电极效应的影响。氮化钛（TiN）是互补金属-氧化物-半导体工艺中常用的电极材料。优化制备 TiN 薄膜的工艺参数可以改变与 HZO 电容器的匹配度，从而找到最佳的 TiN 工艺参数来改善 HZO 的铁电特性。本研究全面考察了原子层沉积（ALD）TiN 关键工艺参数，包括循环次数、TiCl4 和 NH3 脉冲时间、工艺温度（Tp）对薄膜厚度、TiN 晶相、方波电阻率（Rs）、表面平均粗糙度（Ra）和均方根粗糙度（Rq）的影响。结果表明，采用优化 TiN 电极的 HZO 铁电电容器的最大 2 倍残余极化（2Pr）可达到 35.17 µC cm-2，开关周期耐久性超过 8 × 107。
{"title":"Effect of atomic layer deposition process parameters on TiN electrode for Hf0.5Zr0.5O2 ferroelectric capacitor","authors":"Hongbo Li, Jian Zhang, Chongyong Guo, Yuanya Liu, Chunyan Liu, Yu Wang, Jianjun Li, Hui Yuan and Xingcheng Jin","doi":"10.1088/1361-6641/ad7637","DOIUrl":"https://doi.org/10.1088/1361-6641/ad7637","url":null,"abstract":"Hf0.5Zr0.5O2 (HZO), an innovative and exceptional ferroelectric material, exhibits remarkably high sensitivity, making it particularly vulnerable to electrode effect. Titanium nitride (TiN) is a commonly employed as electrode material in the complementary metal–oxide–semiconductor process. Optimizing the process parameters of preparing TiN film can alter matching degree with HZO capacitor, so as to find the optimal parameters of TiN process to improve ferroelectric property of HZO. In this study, the impact of key process parameters in atomic layer deposition (ALD) TiN, including cycle number, TiCl4 and NH3 pulse time, process temperature (Tp) on film thickness, crystalline phases of TiN, square resistivity (Rs), surface average roughness (Ra) and the root-mean-square roughness (Rq) of TiN film are comprehensively investigated. Through optimization, ∼10 nm ALD TiN film can achieve excellent uniformity of 0.43%, low Rs of 286.9 Ω/□, improved Ra and Rq of 1.82 Å and 2.28 Å. The results show that the maximum 2 times remnant polarization (2Pr) of the HZO ferroelectric capacitor with optimized TiN electrodes can reach 35.17 µC cm−2, and the switching cycle endurance exceeds 8 × 107.","PeriodicalId":21585,"journal":{"name":"Semiconductor Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1088/1361-6641/ad7639
Tanmoy Majumder, Chandrima Mukherjee, Sudeb Dasgupta, Udayan Chakraborty, Narottam Das and Abhishek Bhattacharjee
A first time comparative study of the thermal dependence of vital electrical characteristics of two-dimensional metal-oxide-semiconductor field-effect transistors based on black phosphorus for both zigzag and armchair orientations is presented in this paper. It is seen that a higher in-plane thermal conductivity in zigzag direction results in a much better on state current performance which comes at the cost of orders of magnitude increase in gate leakage and a reduced on to off state current ratio. The effect of temperature on threshold voltage (VTH), short channel effects like drain induced barrier lowering, subthreshold swing (SS), Schottky barrier height ΦSB and transconductance behavior in both zigzag and armchair orientations is thoroughly discussed and the inherent physical mechanisms resulting the variations are also presented. Though increase in temperature is found to deteriorate the SS and drain conductance but at the same time, it is found to improve the short channel performance of the devices under consideration.
本文首次对基于黑磷的二维金属氧化物半导体场效应晶体管人字形和扶手椅方向的重要电气特性的热依赖性进行了比较研究。结果表明，人字形方向上较高的面内热导率能带来更好的通态电流性能，但代价是栅极漏电量级的增加和通态与断态电流比的降低。我们深入讨论了温度对阈值电压 (VTH)、短沟道效应（如漏极诱导势垒降低）、阈下摆动 (SS)、肖特基势垒高度 ΦSB 以及人字形和扶手椅方向的跨导行为的影响，并介绍了导致这些变化的内在物理机制。虽然温度升高会降低 SS 和漏极电导，但同时也会改善所研究器件的短沟道性能。
{"title":"The effect of temperature on the electrical characteristics of zigzag and armchair black phosphorus based 2D MOSFET","authors":"Tanmoy Majumder, Chandrima Mukherjee, Sudeb Dasgupta, Udayan Chakraborty, Narottam Das and Abhishek Bhattacharjee","doi":"10.1088/1361-6641/ad7639","DOIUrl":"https://doi.org/10.1088/1361-6641/ad7639","url":null,"abstract":"A first time comparative study of the thermal dependence of vital electrical characteristics of two-dimensional metal-oxide-semiconductor field-effect transistors based on black phosphorus for both zigzag and armchair orientations is presented in this paper. It is seen that a higher in-plane thermal conductivity in zigzag direction results in a much better on state current performance which comes at the cost of orders of magnitude increase in gate leakage and a reduced on to off state current ratio. The effect of temperature on threshold voltage (VTH), short channel effects like drain induced barrier lowering, subthreshold swing (SS), Schottky barrier height ΦSB and transconductance behavior in both zigzag and armchair orientations is thoroughly discussed and the inherent physical mechanisms resulting the variations are also presented. Though increase in temperature is found to deteriorate the SS and drain conductance but at the same time, it is found to improve the short channel performance of the devices under consideration.","PeriodicalId":21585,"journal":{"name":"Semiconductor Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1088/1361-6641/ad7673
Zhen Wang, Peng Jin, Pengfei Qu, Dunzhou Xu, Xiaodi Huo, Ju Wu and Zhanguo Wang
In order to better understand the influence of different complexes on the diamond co-doping system, N and Ga are chosen as co-dopants in diamond. The properties of several substitutional NmGan complexes with vacancy (Va) in the bulk diamond have been investigated by ab initio density functional technique, including their optimized lattice structures, formation energies, binding energies and thermodynamic transition levels. The calculational results show that NmGan complexes in the donor–acceptor–donor (DAD) configuration can provide ionization energies similar to phosphorus-doped diamond. All other complexes provide deep impurity levels. For the DAD configuration, the adsorption process on the diamond surface has been studied to demonstrate the feasibility of growing diamonds containing N-Ga-N in experiments. The desired complex configuration is not uniquely present in the co-doped system. Investigating these properties of different complexes beyond NGaN provides insight into the N and Ga codoped diamond system, yielding a more comprehensive understanding of its potential and limitations. Our research ideas can also be extended to other co-doped systems and help to evaluate other potential co-dopants for diamond.
为了更好地了解不同配合物对金刚石共掺杂体系的影响，我们选择 N 和 Ga 作为金刚石中的共掺杂剂。研究人员利用 ab initio 密度泛函技术研究了大块金刚石中具有空位（Va）的几种取代型 NmGan 复合物的性质，包括它们的优化晶格结构、形成能、结合能和热力学转变水平。计算结果表明，供体-受体-供体（DAD）构型的 NmGan 复合物可提供与掺磷金刚石相似的电离能。所有其他络合物都能提供较深的杂质水平。对于 DAD 构型，我们研究了金刚石表面的吸附过程，以证明在实验中生长含有 N-Ga-N 的金刚石的可行性。在共掺杂体系中，所需的络合物构型并不是唯一存在的。研究 NGaN 以外不同复合物的这些特性，有助于深入了解 N 和 Ga 共掺杂金刚石体系，从而更全面地了解其潜力和局限性。我们的研究思路还可扩展到其他共掺杂体系，并有助于评估金刚石的其他潜在共掺杂剂。
{"title":"The ab initio study of n-type nitrogen and gallium co-doped diamond","authors":"Zhen Wang, Peng Jin, Pengfei Qu, Dunzhou Xu, Xiaodi Huo, Ju Wu and Zhanguo Wang","doi":"10.1088/1361-6641/ad7673","DOIUrl":"https://doi.org/10.1088/1361-6641/ad7673","url":null,"abstract":"In order to better understand the influence of different complexes on the diamond co-doping system, N and Ga are chosen as co-dopants in diamond. The properties of several substitutional NmGan complexes with vacancy (Va) in the bulk diamond have been investigated by ab initio density functional technique, including their optimized lattice structures, formation energies, binding energies and thermodynamic transition levels. The calculational results show that NmGan complexes in the donor–acceptor–donor (DAD) configuration can provide ionization energies similar to phosphorus-doped diamond. All other complexes provide deep impurity levels. For the DAD configuration, the adsorption process on the diamond surface has been studied to demonstrate the feasibility of growing diamonds containing N-Ga-N in experiments. The desired complex configuration is not uniquely present in the co-doped system. Investigating these properties of different complexes beyond NGaN provides insight into the N and Ga codoped diamond system, yielding a more comprehensive understanding of its potential and limitations. Our research ideas can also be extended to other co-doped systems and help to evaluate other potential co-dopants for diamond.","PeriodicalId":21585,"journal":{"name":"Semiconductor Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1088/1361-6641/ad763a
Han Yu, Teng Jiao, Xinming Dang, Yu Han, Yihan Li, Zhen Li, Peiran Chen, Xin Dong, Guoxing Li, Yuantao Zhang and Baolin Zhang
Ga2O3 is a fast-developing wide band semiconductor for solar-blind ultraviolet photodetectors (PDs) applications. The heterojunction self-powered PDs fabricated from heteroepitaxial Ga2O3 films currently have low responsivity and response speed. In this work, we fabricated Schottky barrier PDs based on homoepitaxially grown high quality Ga2O3 films, which exhibited high performance with high responsivity at different bias voltages. In particular, the device achieves a responsivity of 90.3 mA W−1, a photo-to-dark current ratio (PDCR) of 3.2 × 104 and a detectivity of 3.8 × 1013 Jones at 0 V. In addition, a response time of superior to 5 ms is achieved. The results demonstrate the advantages of homoepitaxial Ga2O3 films in the field of high-performance devices.
{"title":"Self-powered Schottky barrier photodetector with high responsivity based on homoepitaxial Ga2O3 films by MOCVD","authors":"Han Yu, Teng Jiao, Xinming Dang, Yu Han, Yihan Li, Zhen Li, Peiran Chen, Xin Dong, Guoxing Li, Yuantao Zhang and Baolin Zhang","doi":"10.1088/1361-6641/ad763a","DOIUrl":"https://doi.org/10.1088/1361-6641/ad763a","url":null,"abstract":"Ga2O3 is a fast-developing wide band semiconductor for solar-blind ultraviolet photodetectors (PDs) applications. The heterojunction self-powered PDs fabricated from heteroepitaxial Ga2O3 films currently have low responsivity and response speed. In this work, we fabricated Schottky barrier PDs based on homoepitaxially grown high quality Ga2O3 films, which exhibited high performance with high responsivity at different bias voltages. In particular, the device achieves a responsivity of 90.3 mA W−1, a photo-to-dark current ratio (PDCR) of 3.2 × 104 and a detectivity of 3.8 × 1013 Jones at 0 V. In addition, a response time of superior to 5 ms is achieved. The results demonstrate the advantages of homoepitaxial Ga2O3 films in the field of high-performance devices.","PeriodicalId":21585,"journal":{"name":"Semiconductor Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1088/1361-6641/ad7638
Xiaorui Wang, Tomáš Vaněk, František Hájek, Vítězslav Jarý, Tomáš Hubáček, Alice Hospodková, Francis Chi-Chung Ling and Shijie Xu
With the sub-bandgap optical excitation, thermal dynamics of holes among multiple levels in n-type GaN epilayers with different dopants of Si, Ge and C are investigated via measuring and modeling variable-temperature yellow luminescence (YL) band of the samples. In sharp contrast to the case of above-bandgap optical excitation, the variable-temperature YL band of all the studied GaN samples including unintentionally-doped sample exhibit unusual negative thermal quenching (NTQ) behavior, suggesting a possible physical mechanism, namely thermally induced migration of holes from shallower levels to the luminescent deep level. By considering the possible presence of multiple hole levels in the doped GaN samples, a phenomenological model is developed for the thermal transfer of holes among the multi-levels and the interpretation of the observed NTQ phenomenon of the YL band. Different activation energies of 347.9, 520.8 and 348.5 meV are obtained for the Ge-doped, high C-containing, and Si-doped GaN samples, respectively. The results reveal the existence of multiple hole defect levels in the n-type GaN. Possible microstructural origins causing these different hole levels are further argued. The study may shed some light on the nature of various defect complexes in the technologically important GaN epilayers. Combined microstructural and optical investigations need to be further done for elucidating various optically- and electrically-active defect complexes in GaN.
在亚带隙光激发下，通过测量和模拟样品的变温黄色发光（YL）带，研究了含有硅、锗和碳等不同掺杂剂的 n 型氮化镓外延层中多级空穴的热动力学。与高带隙光激发的情况形成鲜明对比的是，所有研究的 GaN 样品（包括无意掺杂的样品）的变温 YL 带都表现出不寻常的负热淬灭（NTQ）行为，这表明了一种可能的物理机制，即热诱导空穴从较浅的层次迁移到发光的较深层次。考虑到掺杂氮化镓样品中可能存在多个空穴水平，我们建立了一个多水平之间空穴热转移的现象学模型，并解释了所观察到的 YL 波段的 NTQ 现象。掺杂 Ge、高含 C 和掺杂 Si 的 GaN 样品分别获得了 347.9、520.8 和 348.5 meV 的不同活化能。这些结果揭示了 n 型氮化镓中存在多个空穴缺陷水平。研究还进一步论证了造成这些不同空穴水平的可能微结构根源。这项研究可以揭示具有重要技术意义的氮化镓外延层中各种缺陷复合物的性质。要阐明氮化镓中各种光学和电学活性缺陷复合物，还需要进一步开展微结构和光学联合研究。
{"title":"Sub-bandgap excited photoluminescence probing of deep defect complexes in GaN doped by Si, Ge and C impurities","authors":"Xiaorui Wang, Tomáš Vaněk, František Hájek, Vítězslav Jarý, Tomáš Hubáček, Alice Hospodková, Francis Chi-Chung Ling and Shijie Xu","doi":"10.1088/1361-6641/ad7638","DOIUrl":"https://doi.org/10.1088/1361-6641/ad7638","url":null,"abstract":"With the sub-bandgap optical excitation, thermal dynamics of holes among multiple levels in n-type GaN epilayers with different dopants of Si, Ge and C are investigated via measuring and modeling variable-temperature yellow luminescence (YL) band of the samples. In sharp contrast to the case of above-bandgap optical excitation, the variable-temperature YL band of all the studied GaN samples including unintentionally-doped sample exhibit unusual negative thermal quenching (NTQ) behavior, suggesting a possible physical mechanism, namely thermally induced migration of holes from shallower levels to the luminescent deep level. By considering the possible presence of multiple hole levels in the doped GaN samples, a phenomenological model is developed for the thermal transfer of holes among the multi-levels and the interpretation of the observed NTQ phenomenon of the YL band. Different activation energies of 347.9, 520.8 and 348.5 meV are obtained for the Ge-doped, high C-containing, and Si-doped GaN samples, respectively. The results reveal the existence of multiple hole defect levels in the n-type GaN. Possible microstructural origins causing these different hole levels are further argued. The study may shed some light on the nature of various defect complexes in the technologically important GaN epilayers. Combined microstructural and optical investigations need to be further done for elucidating various optically- and electrically-active defect complexes in GaN.","PeriodicalId":21585,"journal":{"name":"Semiconductor Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-09DOI: 10.1088/1361-6641/ad70d4
M T Sultan, M L Ciurea, I Stavarache, K A Thórarinsdóttir, U B Arnalds, V Teodorescu, A Manolescu, S Ingvarsson, H G Svavarsson
We study the dependence of photo-spectral intensity on tri- and multilayers of SiO2/[SiGe [dSiGe]/SiO2]N with repetitions N = 1 to 10 and thicknesses dSiGe=5–100 nm. Photocurrent analysis reveals a bimodal spectral feature. A comparison of the photocurrent analysis between tri- and multilayers shows that in the multilayer structures, the photo-spectral intensity increases with increasing repetition N. The change in intensity could then be further tuned by changing the thickness of the SiGe layers dSiGe. We attribute the change in intensity to an increase in tensile strain, along with increased Ge atomic concentration and reduced SiGe-nano cluster size.
我们研究了三层和多层 SiO2/[SiGe[dSiGe]/SiO2]N（重复次数 N = 1 至 10，厚度 dSiGe=5-100 nm）光光谱强度的依赖性。光电流分析显示了双峰光谱特征。对三层和多层结构的光电流分析比较表明，在多层结构中，光光谱强度随着重复次数 N 的增加而增加。我们将强度变化归因于拉伸应变的增加、Ge 原子浓度的增加和 SiGe 纳米团簇尺寸的减小。
{"title":"Optimizing photocurrent intensity in layered SiGe heterostructures","authors":"M T Sultan, M L Ciurea, I Stavarache, K A Thórarinsdóttir, U B Arnalds, V Teodorescu, A Manolescu, S Ingvarsson, H G Svavarsson","doi":"10.1088/1361-6641/ad70d4","DOIUrl":"https://doi.org/10.1088/1361-6641/ad70d4","url":null,"abstract":"We study the dependence of photo-spectral intensity on tri- and multilayers of SiO<sub>2</sub>/[SiGe [<inline-formula>\u0000<tex-math><?CDATA $d_mathrm{SiGe}$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:msub><mml:mi>d</mml:mi><mml:mrow><mml:mi>SiGe</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math><inline-graphic xlink:href=\"sstad70d4ieqn1.gif\"></inline-graphic></inline-formula>]/SiO<sub>2</sub>]<sub><italic toggle=\"yes\">N</italic></sub> with repetitions <italic toggle=\"yes\">N</italic> = 1 to 10 and thicknesses <inline-formula>\u0000<tex-math><?CDATA $d_mathrm{SiGe} = 5$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:msub><mml:mi>d</mml:mi><mml:mrow><mml:mi>SiGe</mml:mi></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mn>5</mml:mn></mml:mrow></mml:math><inline-graphic xlink:href=\"sstad70d4ieqn2.gif\"></inline-graphic></inline-formula>–100 nm. Photocurrent analysis reveals a bimodal spectral feature. A comparison of the photocurrent analysis between tri- and multilayers shows that in the multilayer structures, the photo-spectral intensity increases with increasing repetition <italic toggle=\"yes\">N</italic>. The change in intensity could then be further tuned by changing the thickness of the SiGe layers <inline-formula>\u0000<tex-math><?CDATA $d_mathrm{SiGe}$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:msub><mml:mi>d</mml:mi><mml:mrow><mml:mi>SiGe</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math><inline-graphic xlink:href=\"sstad70d4ieqn3.gif\"></inline-graphic></inline-formula>. We attribute the change in intensity to an increase in tensile strain, along with increased Ge atomic concentration and reduced SiGe-nano cluster size.","PeriodicalId":21585,"journal":{"name":"Semiconductor Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-06DOI: 10.1088/1361-6641/ad752a
Yufeng Liu, Yang Shen, Guanpeng Liu, Wenbing Tu, Jiaming Ni
The adsorption of gas molecules (CO, SO) by different atoms (Cu, Fe, Pd, Pt, B, N, P, S) doped graphene has been investigated in terms of adsorption energies, charge transfer, and density of states based on the density functional theory. The Result that the metal atoms enhance the interaction of graphene with the above gas molecules much more than the non-metal atoms, and it is due to this strong interaction that the gas molecules (CO, SO) chemisorb on graphene doped with metal atoms. Meanwhile, the metal atom doped graphene is more sensitive to SO molecules. Moreover, the charge transfer of CO/Pd–G is 0.056e, and the adsorption energy is −6.386 eV, and there is a very large deformation of Pt–G after adsorption of SO and the reaction is very violent, with an adsorption energy up to −7.922 eV and a charge transfer up to 0.537e, which is the highest of all systems. Therefore, we believe that Pt–G is suitable for the detection of the SO while Pd–G is suitable for the detection of the CO. In addition, combined with the nature of the work function, we believe that metal-doped graphene has the potential to be a highly sensitive irreversible sensor.
基于密度泛函理论，从吸附能、电荷转移和状态密度等方面研究了掺杂不同原子（铜、铁、钯、铂、硼、氮、磷、硫）的石墨烯对气体分子（一氧化碳、硫酸）的吸附。结果表明，金属原子比非金属原子更能增强石墨烯与上述气体分子的相互作用，正是由于这种强相互作用，气体分子（CO、SO）才会在掺杂金属原子的石墨烯上发生化学吸附。同时，掺杂金属原子的石墨烯对 SO 分子更为敏感。此外，CO/Pd-G 的电荷转移为 0.056e，吸附能为 -6.386 eV，吸附 SO 后 Pt-G 有非常大的形变，反应非常剧烈，吸附能高达 -7.922 eV，电荷转移高达 0.537e，是所有体系中最高的。因此，我们认为 Pt-G 适合检测 SO，而 Pd-G 适合检测 CO。此外，结合功函数的性质，我们认为掺金属的石墨烯有可能成为一种高灵敏度的不可逆传感器。
{"title":"The adsorption performance of harmful gas (CO, SO) on doped graphene: a first-principle study","authors":"Yufeng Liu, Yang Shen, Guanpeng Liu, Wenbing Tu, Jiaming Ni","doi":"10.1088/1361-6641/ad752a","DOIUrl":"https://doi.org/10.1088/1361-6641/ad752a","url":null,"abstract":"The adsorption of gas molecules (CO, SO) by different atoms (Cu, Fe, Pd, Pt, B, N, P, S) doped graphene has been investigated in terms of adsorption energies, charge transfer, and density of states based on the density functional theory. The Result that the metal atoms enhance the interaction of graphene with the above gas molecules much more than the non-metal atoms, and it is due to this strong interaction that the gas molecules (CO, SO) chemisorb on graphene doped with metal atoms. Meanwhile, the metal atom doped graphene is more sensitive to SO molecules. Moreover, the charge transfer of CO/Pd–G is 0.056e, and the adsorption energy is −6.386 eV, and there is a very large deformation of Pt–G after adsorption of SO and the reaction is very violent, with an adsorption energy up to −7.922 eV and a charge transfer up to 0.537e, which is the highest of all systems. Therefore, we believe that Pt–G is suitable for the detection of the SO while Pd–G is suitable for the detection of the CO. In addition, combined with the nature of the work function, we believe that metal-doped graphene has the potential to be a highly sensitive irreversible sensor.","PeriodicalId":21585,"journal":{"name":"Semiconductor Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-04DOI: 10.1088/1361-6641/ad689e
R A Zaghlool, S R ElShawadfy, F Mohamed, A S Abdel Moghny
Tuning the optical parameters as well as the electrical conductivity of polymer composites is required to match the needs of optical and/or electrolyte-based energy storage devices. Depending on the choice of filler, the addition of small amounts of inorganic fillers to suitable polymers allows this target to be attained. In the present study, polyvinyl alcohol (PVA)/FeCl3/xNiO nanocomposites were prepared using the solution cast method. The structural, optical and electrical properties were investigated before and after irradiating the nanocomposites with gamma radiation at two doses, 300 and 400 Gy. Fourier transform infrared analysis confirmed the interaction of NiO with the PVA/FeCl3 matrix. The nanocomposites show a direct band gap that decreases from 2.47 to 2.25 eV as the NiO content increases from 0% to 7%, while the dc conductivity is increased from 9.15 × 10−8 to 8.46 × 10−7 S cm−1. After irradiation by 400 Gy of gamma radiation, the band gap of the PVA/ FeCl3/7%NiO nanocomposite is increased to 2.33 eV while the dc conductivity decreases to 1.19 × 10−8 S cm−1. On the other hand, the PVA/FeCl3 matrix shows low refractive index, 1.134 at 550 nm, which further increases to 1.213 as the NiO content reaches 7 wt%; this is reduced to 1.211 after exposure to 300 Gy of gamma radiation.
{"title":"Intensive study on gamma-irradiated PVA/FeCl3/NiO nanocomposites for promising applications: structural, optical and electrical","authors":"R A Zaghlool, S R ElShawadfy, F Mohamed, A S Abdel Moghny","doi":"10.1088/1361-6641/ad689e","DOIUrl":"https://doi.org/10.1088/1361-6641/ad689e","url":null,"abstract":"Tuning the optical parameters as well as the electrical conductivity of polymer composites is required to match the needs of optical and/or electrolyte-based energy storage devices. Depending on the choice of filler, the addition of small amounts of inorganic fillers to suitable polymers allows this target to be attained. In the present study, polyvinyl alcohol (PVA)/FeCl<sub>3</sub>/<italic toggle=\"yes\">x</italic>NiO nanocomposites were prepared using the solution cast method. The structural, optical and electrical properties were investigated before and after irradiating the nanocomposites with gamma radiation at two doses, 300 and 400 Gy. Fourier transform infrared analysis confirmed the interaction of NiO with the PVA/FeCl<sub>3</sub> matrix. The nanocomposites show a direct band gap that decreases from 2.47 to 2.25 eV as the NiO content increases from 0% to 7%, while the dc conductivity is increased from 9.15 × 10<sup>−8</sup> to 8.46 × 10<sup>−7</sup> S cm<sup>−1</sup>. After irradiation by 400 Gy of gamma radiation, the band gap of the PVA/ FeCl<sub>3</sub>/7%NiO nanocomposite is increased to 2.33 eV while the dc conductivity decreases to 1.19 × 10<sup>−8</sup> S cm<sup>−1</sup>. On the other hand, the PVA/FeCl<sub>3</sub> matrix shows low refractive index, 1.134 at 550 nm, which further increases to 1.213 as the NiO content reaches 7 wt%; this is reduced to 1.211 after exposure to 300 Gy of gamma radiation.","PeriodicalId":21585,"journal":{"name":"Semiconductor Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-29DOI: 10.1088/1361-6641/ad6c7a
Ziwei Zhou, Guipeng Liu, Guijuan Zhao
In this paper, a temperature- and gate voltage-dependent current–voltage (I–V) model for gallium nitride (GaN) high electron mobility transistors (HEMTs) devices is studied. To help researchers and designers simulate devices in the absence of experimental data and improve the parameter extraction efficiency, the temperature and gate voltage dependence of mobility are discussed and incorporated into the proposed model, which is revised from the standard advanced SPICE model (ASM) for GaN HEMTs. The mobility variations with the gate voltage from −2 V to 6 V and the temperature from 10 K to 1000 K are analyzed. The simulation results of our model are compared with the standard ASM-HEMT model, and the output and transfer characteristics of the device from 270 K to 420 K are simulated. Therefore, our model may simulate various applications of GaN HEMTs at different gate voltages and temperatures in the early stages of design and research.
本文研究了氮化镓（GaN）高电子迁移率晶体管（HEMT）器件与温度和栅极电压有关的电流电压（I-V）模型。为了帮助研究人员和设计人员在缺乏实验数据的情况下模拟器件并提高参数提取效率，本文讨论了迁移率与温度和栅极电压的关系，并将其纳入了所提出的模型，该模型是在氮化镓高电子迁移率晶体管的标准高级 SPICE 模型 (ASM) 基础上修订而成的。分析了栅极电压从 -2 V 到 6 V 以及温度从 10 K 到 1000 K 时的迁移率变化。我们将模型的模拟结果与标准 ASM-HEMT 模型进行了比较，并模拟了器件在 270 K 至 420 K 温度范围内的输出和传输特性。因此，在设计和研究的早期阶段，我们的模型可以模拟 GaN HEMT 在不同栅极电压和温度下的各种应用。
{"title":"Temperature- and gate voltage-dependent I–V modeling of GaN HEMTs based on ASM-HEMT","authors":"Ziwei Zhou, Guipeng Liu, Guijuan Zhao","doi":"10.1088/1361-6641/ad6c7a","DOIUrl":"https://doi.org/10.1088/1361-6641/ad6c7a","url":null,"abstract":"In this paper, a temperature- and gate voltage-dependent current–voltage (<italic toggle=\"yes\">I</italic>–<italic toggle=\"yes\">V</italic>) model for gallium nitride (GaN) high electron mobility transistors (HEMTs) devices is studied. To help researchers and designers simulate devices in the absence of experimental data and improve the parameter extraction efficiency, the temperature and gate voltage dependence of mobility are discussed and incorporated into the proposed model, which is revised from the standard advanced SPICE model (ASM) for GaN HEMTs. The mobility variations with the gate voltage from −2 V to 6 V and the temperature from 10 K to 1000 K are analyzed. The simulation results of our model are compared with the standard ASM-HEMT model, and the output and transfer characteristics of the device from 270 K to 420 K are simulated. Therefore, our model may simulate various applications of GaN HEMTs at different gate voltages and temperatures in the early stages of design and research.","PeriodicalId":21585,"journal":{"name":"Semiconductor Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-28DOI: 10.1088/1361-6641/ad70d5
H Yazdani, F Brunner, A Thies, H J Würfl, O Hilt
In this work, Si implantation and activation for lowering the ohmic contact resistance (Rc) of mm-wave GaN HEMTs has been investigated. Various combinations of annealing temperature/duration and implantation doses were tested. Dopant activation was performed using a modified procedure in an MOCVD tool, involving fast temperature ramping and annealing the samples for 8 min at 1150 °C. Thereby, ∼0.02 ± 0.01 Ω mm contact resistance was achieved on a fully doped region and ∼0.1 ± 0.02 Ω mm when only the source and drain contact region was n-type doped. For comparison, a well-established alloyed Ti/Al/Ni/Au ohmic contact scheme without implantation, was used as reference resulting in an average Rc ∼ 0.34 ± 0.12 Ω mm on the same wafer. Besides the three times lowered contact resistance the implanted contacts also showed a significantly improved on-wafer homogeneity.
{"title":"Si-implantation for low ohmic contact resistances in RF GaN HEMTs","authors":"H Yazdani, F Brunner, A Thies, H J Würfl, O Hilt","doi":"10.1088/1361-6641/ad70d5","DOIUrl":"https://doi.org/10.1088/1361-6641/ad70d5","url":null,"abstract":"In this work, Si implantation and activation for lowering the ohmic contact resistance (<italic toggle=\"yes\">R</italic><sub>c</sub>) of mm-wave GaN HEMTs has been investigated. Various combinations of annealing temperature/duration and implantation doses were tested. Dopant activation was performed using a modified procedure in an MOCVD tool, involving fast temperature ramping and annealing the samples for 8 min at 1150 °C. Thereby, ∼0.02 ± 0.01 Ω mm contact resistance was achieved on a fully doped region and ∼0.1 ± 0.02 Ω mm when only the source and drain contact region was n-type doped. For comparison, a well-established alloyed Ti/Al/Ni/Au ohmic contact scheme without implantation, was used as reference resulting in an average <italic toggle=\"yes\">R</italic><sub>c</sub> ∼ 0.34 ± 0.12 Ω mm on the same wafer. Besides the three times lowered contact resistance the implanted contacts also showed a significantly improved on-wafer homogeneity.","PeriodicalId":21585,"journal":{"name":"Semiconductor Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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