Sangita R. Panda, Manoranjan Pradhan, Sandipan Mallik, Trinath Sahu
We analyze the asymmetric doping‐dependent electron mobility μ of GaAs/InGaAs/GaAs quantum well field‐effect transistor (QWFET) structure. We consider doping concentrations, nd1 and nd2, in the substrate and surface barriers, respectively, and study μ as a function of nd2, taking (nd1 + nd2) unchanged. An increase in nd2 decreases nd1, yielding interesting changes in the occupation of subbands. For well width W < 164 Å, μ is due to single subband occupancy (SSO). Around W = 164 Å, there occurs first SSO, then double subband occupancy (DSO), and again SSO with an increase in nd2. Near the transition of subbands, abrupt discontinuities in μ arise due to inter‐subband effects. Thus, high to low and then high values of μ are obtained, displaying almost flat‐like variations, symmetric about |nd2 − nd1| =0. As W becomes wider, complete DSO occurs throughout the range of nd2 having reduced μ. Alternatively, keeping nd1 unchanged and by increasing nd2,μ raises due to enhanced Ns, with a drop near the transition from SSO to DSO. Under SSO, μ is controlled by the ionized impurity and alloy disorder scatterings, while under DSO, the impurity scattering determines μ. Our analysis on μ can help to examine the inter‐subband effects on device characteristics of the QWFET system.
我们分析了 GaAs/InGaAs/GaAs 量子阱场效应晶体管 (QWFET) 结构的非对称掺杂电子迁移率 μ。我们分别考虑了衬底和表面势垒中的掺杂浓度 nd1 和 nd2，在 (nd1 + nd2) 不变的情况下，研究了 μ 与 nd2 的函数关系。nd2的增大会减小nd1，从而使子带的占有率发生有趣的变化。在井宽 W < 164 Å 时，μ 是由于单子带占据（SSO）造成的。在 W = 164 Å 附近，首先出现的是 SSO，然后是双子带占用（DSO），随着 nd2 的增加，再次出现 SSO。在子带过渡附近，由于子带之间的影响，μ 出现了突然的不连续性。因此，μ 的值从高到低再到高，几乎呈扁平状变化，对称于 |nd2 - nd1| = 0。或者，保持 nd1 不变并增加 nd2，μ 会因 N s 的增加而升高，并在从 SSO 过渡到 DSO 附近下降。在 SSO 条件下，μ 受电离杂质和合金无序散射的控制，而在 DSO 条件下，杂质散射决定μ。我们对 μ 的分析有助于研究子带间效应对 QWFET 系统器件特性的影响。
{"title":"Asymmetric Doping‐Dependent Electron Transport Mobility in InxGa1–xAs/GaAs Quantum Well Field‐Effect Transistor Structure","authors":"Sangita R. Panda, Manoranjan Pradhan, Sandipan Mallik, Trinath Sahu","doi":"10.1002/pssb.202400206","DOIUrl":"https://doi.org/10.1002/pssb.202400206","url":null,"abstract":"We analyze the asymmetric doping‐dependent electron mobility <jats:italic>μ</jats:italic> of GaAs/InGaAs/GaAs quantum well field‐effect transistor (QWFET) structure. We consider doping concentrations, <jats:italic>nd1</jats:italic> and <jats:italic>nd2</jats:italic>, in the substrate and surface barriers, respectively, and study <jats:italic>μ</jats:italic> as a function of <jats:italic>nd2</jats:italic>, taking (<jats:italic>nd1 </jats:italic>+<jats:italic> nd2</jats:italic>) unchanged. An increase in <jats:italic>nd2</jats:italic> decreases <jats:italic>nd1</jats:italic>, yielding interesting changes in the occupation of subbands. For well width <jats:italic>W</jats:italic> < 164 Å, <jats:italic>μ</jats:italic> is due to single subband occupancy (SSO). Around <jats:italic>W</jats:italic> = 164 Å, there occurs first SSO, then double subband occupancy (DSO), and again SSO with an increase in <jats:italic>nd2</jats:italic>. Near the transition of subbands, abrupt discontinuities in <jats:italic>μ</jats:italic> arise due to inter‐subband effects. Thus, high to low and then high values of <jats:italic>μ</jats:italic> are obtained, displaying almost flat‐like variations, symmetric about |<jats:italic>nd</jats:italic>2 − <jats:italic>nd1</jats:italic>| =<jats:italic> </jats:italic>0. As <jats:italic>W</jats:italic> becomes wider, complete DSO occurs throughout the range of <jats:italic>nd2</jats:italic> having reduced <jats:italic>μ</jats:italic>. Alternatively, keeping <jats:italic>nd1</jats:italic> unchanged and by increasing <jats:italic>nd2,</jats:italic> <jats:italic>μ</jats:italic> raises due to enhanced <jats:italic>N</jats:italic> <jats:sub> <jats:italic>s</jats:italic> </jats:sub>, with a drop near the transition from SSO to DSO. Under SSO, <jats:italic>μ</jats:italic> is controlled by the ionized impurity and alloy disorder scatterings, while under DSO, the impurity scattering determines <jats:italic>μ</jats:italic>. Our analysis on <jats:italic>μ</jats:italic> can help to examine the inter‐subband effects on device characteristics of the QWFET system.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"96 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141866444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nikolai A. Poklonski, Ilya I. Anikeev, Sergey A. Vyrko, Andrei G. Zabrodskii
A model of tunneling (jumping) migration of charge carriers near their mobility edge in the upper band of neutral states of majority hydrogen‐like impurities is proposed to calculate the energy of thermal activation of electrical ‐conductivity of weakly compensated semiconductors. The difference from the known Hubbard model consists in the scheme of interimpurity transitions of charge carriers and in the method of calculating the position of their tunnel mobility edge. The drift mobility edge of free charge carriers corresponds to the thermal ionization energy of majority impurities , which is located near the c‐band bottom or the v‐band top in n‐ and p‐type semiconductors, respectively, and is due to the overlap of excited states of electrically neutral majority impurities. The position of the tunnel mobility edge for ‐conductivity is determined by taking into account the Coulomb interaction of the majority impurities in the charge states and . It is assumed that doping and compensating impurities form a single simple nonstoichiometric cubic lattice in a crystal matrix. The calculations of the activation energy on the insulator side of the insulator–metal concentration phase transition for weakly compensated p‐Si:B, n‐Si:P, and n‐Ge:Sb crystals quantitatively agree with known experimental data.
为了计算弱补偿半导体电导热激活的能量，我们提出了电荷载流子在多数氢类杂质的中性态上带迁移率边缘附近的隧道（跳跃）迁移模型。与已知哈伯德模型的不同之处在于电荷载流子的杂质间跃迁方案及其隧道迁移率边缘位置的计算方法。自由电荷载流子的漂移迁移率边沿与多数杂质的热电离能相对应，在 n 型和 p 型半导体中分别位于 c 带底部或 v 带顶部附近，这是由于电中性多数杂质的激发态重叠造成的。考虑到多数杂质在电荷态中的库仑相互作用以及掺杂和补偿杂质在晶体基质中形成单个简单的非化学计量立方晶格，确定了-导电性隧道迁移率边缘的位置。对弱补偿 p-Si:B、n-Si:P 和 n-Ge:Sb 晶体的绝缘体-金属浓度相变的绝缘体侧活化能的计算结果与已知实验数据定量一致。
{"title":"Calculation of the Activation Energy of Electrical ε2‐Conductivity of Weakly Compensated Semiconductors","authors":"Nikolai A. Poklonski, Ilya I. Anikeev, Sergey A. Vyrko, Andrei G. Zabrodskii","doi":"10.1002/pssb.202400178","DOIUrl":"https://doi.org/10.1002/pssb.202400178","url":null,"abstract":"A model of tunneling (jumping) migration of charge carriers near their mobility edge in the upper band of neutral states of majority hydrogen‐like impurities is proposed to calculate the energy of thermal activation of electrical ‐conductivity of weakly compensated semiconductors. The difference from the known Hubbard model consists in the scheme of interimpurity transitions of charge carriers and in the method of calculating the position of their tunnel mobility edge. The drift mobility edge of free charge carriers corresponds to the thermal ionization energy of majority impurities , which is located near the <jats:italic>c</jats:italic>‐band bottom or the <jats:italic>v</jats:italic>‐band top in <jats:italic>n</jats:italic>‐ and <jats:italic>p</jats:italic>‐type semiconductors, respectively, and is due to the overlap of excited states of electrically neutral majority impurities. The position of the tunnel mobility edge for ‐conductivity is determined by taking into account the Coulomb interaction of the majority impurities in the charge states and . It is assumed that doping and compensating impurities form a single simple nonstoichiometric cubic lattice in a crystal matrix. The calculations of the activation energy on the insulator side of the insulator–metal concentration phase transition for weakly compensated <jats:italic>p</jats:italic>‐Si:B, <jats:italic>n</jats:italic>‐Si:P, and <jats:italic>n</jats:italic>‐Ge:Sb crystals quantitatively agree with known experimental data.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"10 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141866445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The poor conductivity of β‐Ga2O3 limits its application in optoelectronic devices. Currently, there have been advancements in investigating the impact of Mo doping on the photoelectric characteristics of β‐Ga2O3. However, there are few studies on the impact of different valence states of Mo doping and the coexistence of O vacancy and interstitial H on the electrical properties of β‐Ga2O3. In the process of preparing β‐Ga2O3, O vacancy and interstitial H inevitably exist. In response to these problems, the first‐principles GGA + U method is used to study the impact of different valence states of Mo doping and the coexistence of interstitial H and O vacancy on the electrical properties of β‐Ga2O3. The electronic structure, mobility, conductivity, and carrier lifetime of the system are calculated and analyzed. The results show that all doping systems are more stable under Ga‐rich conditions. The band gap of the Mo‐doped β‐Ga2O3 system gradually narrows, which is mainly attributed to the Burstein–Moss effect and the multiplicity reintegration effect. Mo doping effectively improves the electrical conductivity of the system. Ga47O72Mo16+H11+ system has the longest carrier lifetime; Ga47O72Mo16+H10 has the largest mobility; Ga47O72Mo15+H10 system has the highest conductivity. Therefore, Mo‐doped β‐Ga2O3 materials help to prepare new electrical performance devices.
β-Ga2O3 的导电性较差，限制了其在光电设备中的应用。目前，在研究掺杂 Mo 对 β-Ga2O3 光电特性的影响方面取得了进展。然而，有关掺杂 Mo 的不同价态以及 O 空位和间隙 H 共存对 β-Ga2O3 电学特性影响的研究却很少。在制备 β-Ga2O3 的过程中，不可避免地会存在 O 空位和间隙 H。针对这些问题，采用第一原理 GGA + U 方法研究了掺杂 Mo 的不同价态以及间隙 H 和 O 空位共存对 β-Ga2O3 电学性质的影响。计算并分析了该体系的电子结构、迁移率、电导率和载流子寿命。结果表明，所有掺杂体系在富镓条件下都更加稳定。掺杂 Mo 的 β-Ga2O3 体系的带隙逐渐变窄，这主要归因于 Burstein-Moss 效应和多重再整合效应。掺杂 Mo 有效地提高了体系的导电性。Ga47O72Mo16+H11+体系的载流子寿命最长；Ga47O72Mo16+H10体系的迁移率最大；Ga47O72Mo15+H10体系的导电率最高。因此，掺杂 Mo 的 β-Ga2O3 材料有助于制备新型电性能器件。
{"title":"First‐Principles Study on the Effects of Different Valence Hi and VO on the Mobility, Conductivity, and Carrier Lifetime of β‐Ga2O3: Mo5+/6+","authors":"Xia Liu, Shumin Wen, Dingdu Chen, Wei Wang, Xiurong Feng, Erjun Zhao","doi":"10.1002/pssb.202400229","DOIUrl":"https://doi.org/10.1002/pssb.202400229","url":null,"abstract":"The poor conductivity of β‐Ga<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> limits its application in optoelectronic devices. Currently, there have been advancements in investigating the impact of Mo doping on the photoelectric characteristics of β‐Ga<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>. However, there are few studies on the impact of different valence states of Mo doping and the coexistence of O vacancy and interstitial H on the electrical properties of β‐Ga<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>. In the process of preparing β‐Ga<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>, O vacancy and interstitial H inevitably exist. In response to these problems, the first‐principles GGA + U method is used to study the impact of different valence states of Mo doping and the coexistence of interstitial H and O vacancy on the electrical properties of β‐Ga<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>. The electronic structure, mobility, conductivity, and carrier lifetime of the system are calculated and analyzed. The results show that all doping systems are more stable under Ga‐rich conditions. The band gap of the Mo‐doped β‐Ga<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> system gradually narrows, which is mainly attributed to the Burstein–Moss effect and the multiplicity reintegration effect. Mo doping effectively improves the electrical conductivity of the system. Ga<jats:sub>47</jats:sub>O<jats:sub>72</jats:sub>Mo<jats:sub>1</jats:sub><jats:sup>6+</jats:sup>H<jats:sub>1</jats:sub><jats:sup>1+</jats:sup> system has the longest carrier lifetime; Ga<jats:sub>47</jats:sub>O<jats:sub>72</jats:sub>Mo<jats:sub>1</jats:sub><jats:sup>6+</jats:sup>H<jats:sub>1</jats:sub><jats:sup>0</jats:sup> has the largest mobility; Ga<jats:sub>47</jats:sub>O<jats:sub>72</jats:sub>Mo<jats:sub>1</jats:sub><jats:sup>5+</jats:sup>H<jats:sub>1</jats:sub><jats:sup>0</jats:sup> system has the highest conductivity. Therefore, Mo‐doped β‐Ga<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> materials help to prepare new electrical performance devices.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"61 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141866475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article utilizes first‐principles calculations within the density functional theory framework, employing spin generalized gradient approximation, to investigate the spin polarization of arsenic nitride nanotubes (AsNNTs). It is found that AsNNT does not exhibit spin polarization and has a bandgap of 1.05 eV, indicating that it is a semiconductor. Decoration with C, O, Ge, and Se on AsNNT induces spin polarization, resulting in magnetic moments of 1.001, 0.916, 0.770, and 0.967 μB, respectively. Meanwhile, all decorated configurations exhibit narrow bandgap semiconductor properties. Furthermore, the nonequilibrium Green's function method is used to study the spin‐polarized current of AsNNT decorated with C, O, Ge, and Se. It is found that AsNNTs decorated with C, Ge, and Se have relatively small spin current values. Notably, the Se‐decorated AsNNT exhibits the highest degree of spin polarization, with the spin current being nearly fully polarized.
本文利用密度泛函理论框架内的第一原理计算，采用自旋广义梯度近似，研究了氮化砷纳米管（AsNNTs）的自旋极化。研究发现，氮化砷纳米管不表现自旋极化，其带隙为 1.05 eV，表明它是一种半导体。在 AsNNT 上装饰 C、O、Ge 和 Se 会诱发自旋极化，导致磁矩分别为 1.001、0.916、0.770 和 0.967 μB。同时，所有装饰构型都表现出窄带隙半导体特性。此外，还利用非平衡格林函数法研究了用 C、O、Ge 和 Se 装饰的 AsNNT 的自旋极化电流。研究发现，用 C、Ge 和 Se 装饰的 AsNNT 具有相对较小的自旋电流值。值得注意的是，Se 装饰的 AsNNT 自旋极化程度最高，自旋电流几乎完全极化。
{"title":"First‐Principles Study on the Spin Polarization of Single‐Walled Arsenic Nitride Nanotubes Decorated with C, O, Ge, and Se","authors":"Hanze Zhu, Mavlanjan Rahman","doi":"10.1002/pssb.202400249","DOIUrl":"https://doi.org/10.1002/pssb.202400249","url":null,"abstract":"This article utilizes first‐principles calculations within the density functional theory framework, employing spin generalized gradient approximation, to investigate the spin polarization of arsenic nitride nanotubes (AsNNTs). It is found that AsNNT does not exhibit spin polarization and has a bandgap of 1.05 eV, indicating that it is a semiconductor. Decoration with C, O, Ge, and Se on AsNNT induces spin polarization, resulting in magnetic moments of 1.001, 0.916, 0.770, and 0.967 μB, respectively. Meanwhile, all decorated configurations exhibit narrow bandgap semiconductor properties. Furthermore, the nonequilibrium Green's function method is used to study the spin‐polarized current of AsNNT decorated with C, O, Ge, and Se. It is found that AsNNTs decorated with C, Ge, and Se have relatively small spin current values. Notably, the Se‐decorated AsNNT exhibits the highest degree of spin polarization, with the spin current being nearly fully polarized.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"166 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Considering the synthesis of novel 2D monolayers such as W8Se12, which are ideal for nanoelectronics, in this study, density‐functional theory is utilized to examine M8X12/G (M = Mo, W; X = S, Se) van der Waals heterostructures (vdWHs). Herein, the crucial role of intrinsic Ohmic contacts and Schottky barrier heights (SBH) at metal/semiconductor interfaces in these heterojunctions, which are vital for efficient current flow and minimal resistance, and their impact on high‐performance electronic and bipolar device applications are focused on. In these findings, it is revealed that W8Se12/G forms an Ohmic contact with a 75.4% tunneling probability, while Mo8S12/G, W8S12/G, and Mo8Se12/G develop n‐type Schottky contacts with remarkably low SBHs of 0.110, 0.136, and 0.064 eV, respectively. The adaptability of these Schottky barriers is demonstrated by modifying the interlayer distance or applying an electric field, leading to transitions from n‐type to p‐type contacts. Additionally, mechanical strain influences the contact type, offering valuable insights for future nanoelectronic and bipolar device technologies. This comprehensive analysis underlines the versatile electronic behavior of M8X12/G vdWHs, highlighting their potential in advancing nanoelectronic devices.
考虑到 W8Se12 等新型二维单层的合成非常适合纳米电子学，本研究利用密度函数理论研究了 M8X12/G（M = Mo、W；X = S、Se）范德华异质结构（vdWHs）。在这里，研究重点是这些异质结中金属/半导体界面上的本征欧姆接触和肖特基势垒高度（SBH）的关键作用，它们对高效电流流动和最小电阻至关重要，以及它们对高性能电子和双极器件应用的影响。研究结果表明，W8Se12/G 形成的欧姆接触的隧穿概率为 75.4%，而 Mo8S12/G、W8Se12/G 和 Mo8Se12/G 形成的 n 型肖特基接触的 SBH 值极低，分别为 0.110、0.136 和 0.064 eV。通过改变层间距离或施加电场，这些肖特基势垒的适应性得到了证明，从而实现了从 n 型触点到 p 型触点的转变。此外，机械应变也会影响接触类型，这为未来的纳米电子和双极器件技术提供了宝贵的启示。这项综合分析强调了 M8X12/G vdWHs 的多功能电子行为，凸显了它们在推动纳米电子器件发展方面的潜力。
{"title":"Intrinsic Ohmic Contacts and Polarity‐Tunable Schottky Barriers in M8X12–Graphene (M = Mo, W; X = S, Se) van der Waals Heterostructures for High‐Performance and Bipolar Device Applications","authors":"Yuehua Xu, Qiang Zeng","doi":"10.1002/pssb.202400164","DOIUrl":"https://doi.org/10.1002/pssb.202400164","url":null,"abstract":"Considering the synthesis of novel 2D monolayers such as W<jats:sub>8</jats:sub>Se<jats:sub>1</jats:sub><jats:sub>2</jats:sub>, which are ideal for nanoelectronics, in this study, density‐functional theory is utilized to examine M<jats:sub>8</jats:sub>X<jats:sub>1</jats:sub><jats:sub>2</jats:sub>/G (M = Mo, W; X = S, Se) van der Waals heterostructures (vdWHs). Herein, the crucial role of intrinsic Ohmic contacts and Schottky barrier heights (SBH) at metal/semiconductor interfaces in these heterojunctions, which are vital for efficient current flow and minimal resistance, and their impact on high‐performance electronic and bipolar device applications are focused on. In these findings, it is revealed that W<jats:sub>8</jats:sub>Se<jats:sub>1</jats:sub><jats:sub>2</jats:sub>/G forms an Ohmic contact with a 75.4% tunneling probability, while Mo<jats:sub>8</jats:sub>S<jats:sub>1</jats:sub><jats:sub>2</jats:sub>/G, W<jats:sub>8</jats:sub>S<jats:sub>1</jats:sub><jats:sub>2</jats:sub>/G, and Mo<jats:sub>8</jats:sub>Se<jats:sub>1</jats:sub><jats:sub>2</jats:sub>/G develop n‐type Schottky contacts with remarkably low SBHs of 0.110, 0.136, and 0.064 eV, respectively. The adaptability of these Schottky barriers is demonstrated by modifying the interlayer distance or applying an electric field, leading to transitions from n‐type to p‐type contacts. Additionally, mechanical strain influences the contact type, offering valuable insights for future nanoelectronic and bipolar device technologies. This comprehensive analysis underlines the versatile electronic behavior of M<jats:sub>8</jats:sub>X<jats:sub>1</jats:sub><jats:sub>2</jats:sub>/G vdWHs, highlighting their potential in advancing nanoelectronic devices.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"19 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Oleksandra Ivakhno‐Tsehelnyk, Oleksandr Selyshchev, Serhiy Kondratenko, Volodymyr Dzhagan, Dietrich R. T. Zahn
Element substitution in Cu2ZnSnS4‐like chalcogenides offers the potential to create alternative low‐cost photovoltaic and thermoelectric materials with tunable properties. In this work, the “green” synthesis of colloidal cation‐substituted Cu–Ni–Sn–S nanocrystals (CNTS NCs) in aqueous solutions using thioglycolic acid as a stabilizer is reported for the first time. The structural and optical properties of CNTS NCs are studied in colloidal solutions and thin films, and are compared with those of Cu–Zn–Sn–S (CZTS) NCs obtained under similar conditions. The NC sizes of both compounds are estimated to be in the range of 1.5–2.5 nm. Both NCs exhibit strongly non‐stoichiometric composition and a structure corresponding to cationically disordered kesterite Cu2ZnSnS4, which are common features of such quaternary metal‐based chalcogenides. The phonon Raman spectra of CNTS and CZTS NCs exhibit very similar lineshapes, but the CNTS phonon band has a larger width and lower frequency, presumably due to stronger cation disorder. The absorption of both types of NCs extends continuously through the visible range with an estimated bandgap of ≈2.2 eV and sub‐bandgap absorption due to an Urbach tail. The absorption coefficient of CNTS is determined to be α > 102 cm−1 at 700 nm and α > 104 cm−1 at 400 nm.
{"title":"“Green” Aqueous Synthesis, Structural, and Optical Properties of Quaternary Cu2ZnSnS4 and Cu2NiSnS4 Nanocrystals","authors":"Oleksandra Ivakhno‐Tsehelnyk, Oleksandr Selyshchev, Serhiy Kondratenko, Volodymyr Dzhagan, Dietrich R. T. Zahn","doi":"10.1002/pssb.202400203","DOIUrl":"https://doi.org/10.1002/pssb.202400203","url":null,"abstract":"Element substitution in Cu<jats:sub>2</jats:sub>ZnSnS<jats:sub>4</jats:sub>‐like chalcogenides offers the potential to create alternative low‐cost photovoltaic and thermoelectric materials with tunable properties. In this work, the “green” synthesis of colloidal cation‐substituted Cu–Ni–Sn–S nanocrystals (CNTS NCs) in aqueous solutions using thioglycolic acid as a stabilizer is reported for the first time. The structural and optical properties of CNTS NCs are studied in colloidal solutions and thin films, and are compared with those of Cu–Zn–Sn–S (CZTS) NCs obtained under similar conditions. The NC sizes of both compounds are estimated to be in the range of 1.5–2.5 nm. Both NCs exhibit strongly non‐stoichiometric composition and a structure corresponding to cationically disordered kesterite Cu<jats:sub>2</jats:sub>ZnSnS<jats:sub>4</jats:sub>, which are common features of such quaternary metal‐based chalcogenides. The phonon Raman spectra of CNTS and CZTS NCs exhibit very similar lineshapes, but the CNTS phonon band has a larger width and lower frequency, presumably due to stronger cation disorder. The absorption of both types of NCs extends continuously through the visible range with an estimated bandgap of ≈2.2 eV and sub‐bandgap absorption due to an Urbach tail. The absorption coefficient of CNTS is determined to be <jats:italic>α</jats:italic> > 10<jats:sup>2</jats:sup> cm<jats:sup>−1</jats:sup> at 700 nm and <jats:italic>α</jats:italic> > 10<jats:sup>4</jats:sup> cm<jats:sup>−1</jats:sup> at 400 nm.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"126 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
James N. Grima‐Cornish, Daphne Attard, Alfred Gatt, Giovanni Ficarra, Dario Cerasola, Claire Saliba Thorne, Andrew Albanozzo, Paul Albanozzo, Ruben Gatt, Cynthia Formosa, Joseph N Grima
Rowing is a sport that requires athletes to perform the action of pulling and rotating an oar by hand, applying forces of considerable magnitude. Herein, inspired by the notion that auxetic materials and metamaterials behave differently compared to their conventional counterparts, it is examined how a handle prototype, specifically designed to incorporate the classic re‐entrant motif, behaves and how end‐users perceive it. Physical experiments conducted on such prototype, which measured the contact pressures, suggest that on average, higher pressures are measured when pulling with this reentrant grip compared to its non reentrant counterpart, indicating that this re‐entrant prototype should feel firmer. More importantly, respondents of a survey are asked to give their feedback, and different views on which handle they would prefer to use are provided. The ones who preferred the prototype with the reentrant features report that they preferred it because it felt firmer and allowed for a better grip. This suggests that there is potential for further investigation into whether handles, oar handles in particular, made from auxetic components, re‐entrant cells, or other motifs which are well known for their negative Poisson's ratio characteristics, could provide a better and more secure grip and be used in sports applications.
{"title":"Handles with Reentrant Cells for Use as Oar Handles: Design Considerations, Physical Characteristics, and End‐Users’ Perceptions","authors":"James N. Grima‐Cornish, Daphne Attard, Alfred Gatt, Giovanni Ficarra, Dario Cerasola, Claire Saliba Thorne, Andrew Albanozzo, Paul Albanozzo, Ruben Gatt, Cynthia Formosa, Joseph N Grima","doi":"10.1002/pssb.202400300","DOIUrl":"https://doi.org/10.1002/pssb.202400300","url":null,"abstract":"Rowing is a sport that requires athletes to perform the action of pulling and rotating an oar by hand, applying forces of considerable magnitude. Herein, inspired by the notion that auxetic materials and metamaterials behave differently compared to their conventional counterparts, it is examined how a handle prototype, specifically designed to incorporate the classic re‐entrant motif, behaves and how end‐users perceive it. Physical experiments conducted on such prototype, which measured the contact pressures, suggest that on average, higher pressures are measured when pulling with this reentrant grip compared to its non reentrant counterpart, indicating that this re‐entrant prototype should feel firmer. More importantly, respondents of a survey are asked to give their feedback, and different views on which handle they would prefer to use are provided. The ones who preferred the prototype with the reentrant features report that they preferred it because it felt firmer and allowed for a better grip. This suggests that there is potential for further investigation into whether handles, oar handles in particular, made from auxetic components, re‐entrant cells, or other motifs which are well known for their negative Poisson's ratio characteristics, could provide a better and more secure grip and be used in sports applications.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"1 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Navneet Kumar Karn, Yogesh Kumar, Geet Awana, Veer Pal Singh Awana
The current article investigates the band structure in the presence and absence of spin‐orbit coupling (SOC), examines the Z2 invariants, and investigates the detailed angle‐dependent magneto‐transport of up to 10 T (Tesla) and down to 2 K for the bismuth crystal. The out‐of‐plane field‐dependent magnetoresistance (MR) is positive and is huge to the order of ≈104% at 2 K and 10 T. On the contrary, the longitudinal (in‐plane) field‐dependent MR is relatively small and is negative. The thermal activation energy is also estimated by using the Boltzmann formula from resistivity versus temperature measurement under applied transverse magnetic fields. The topological nature of Bi is confirmed by Z2 invariant calculation using density functional theory (DFT). PBESol bands show trivial but hybrid functional (HSE) bands show non‐trivial topology being present in Bismuth. This article comprehensively studies the dependence of MR oscillations upon the angle between the applied field and the current. The observed oscillations fade away as the angle is increased. This article is an extension of our previous work on bismuth (J. Sup. Novel Mag. 2023, 36, 389), in which a comprehensive analysis of its structural and micro‐structural properties is conducted along with its transport behavior in an applied transverse magnetic field.
本文研究了铋晶体在存在和不存在自旋轨道耦合（SOC）情况下的带状结构，考察了 Z2 不变量，并详细研究了铋晶体在高达 10 T（特斯拉）和低至 2 K 时随角度变化的磁传输。在 2 K 和 10 T 时，平面外磁场相关磁阻（MR）为正值，且数量级高达 ≈104%。根据横向磁场作用下电阻率与温度关系的测量结果，我们还利用波尔兹曼公式估算了热活化能。利用密度泛函理论（DFT）进行的 Z2 不变计算证实了 Bi 的拓扑性质。铋中的 PBESol 带显示出琐碎性，但混合功能（HSE）带则显示出非琐碎拓扑性。本文全面研究了磁共振振荡与外加电场和电流之间角度的关系。观察到的振荡随着角度的增大而减弱。这篇文章是我们之前关于铋的研究成果（J. Sup. Novel Mag.
{"title":"Investigation of Angle‐Dependent Shubnikov‐de Haas Oscillations in Topological Insulator Bismuth","authors":"Navneet Kumar Karn, Yogesh Kumar, Geet Awana, Veer Pal Singh Awana","doi":"10.1002/pssb.202400077","DOIUrl":"https://doi.org/10.1002/pssb.202400077","url":null,"abstract":"The current article investigates the band structure in the presence and absence of spin‐orbit coupling (SOC), examines the Z2 invariants, and investigates the detailed angle‐dependent magneto‐transport of up to 10 T (Tesla) and down to 2 K for the bismuth crystal. The out‐of‐plane field‐dependent magnetoresistance (MR) is positive and is huge to the order of ≈10<jats:sup>4</jats:sup>% at 2 K and 10 T. On the contrary, the longitudinal (in‐plane) field‐dependent MR is relatively small and is negative. The thermal activation energy is also estimated by using the Boltzmann formula from resistivity versus temperature measurement under applied transverse magnetic fields. The topological nature of Bi is confirmed by Z2 invariant calculation using density functional theory (DFT). PBESol bands show trivial but hybrid functional (HSE) bands show non‐trivial topology being present in Bismuth. This article comprehensively studies the dependence of MR oscillations upon the angle between the applied field and the current. The observed oscillations fade away as the angle is increased. This article is an extension of our previous work on bismuth (<jats:italic>J. Sup. Novel Mag.</jats:italic> 2023, 36, 389), in which a comprehensive analysis of its structural and micro‐structural properties is conducted along with its transport behavior in an applied transverse magnetic field.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"19 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nano‐fourier transform infrared spectroscopy (FTIR) is a powerful tool to measure optical and electronic properties of materials at the nanoscale. It is especially useful for visualizing plasmon and phonon polaritons launched from edges of a sample or structures on top of it. Herein, an exfoliated hexagonal boron nitride flake with a thickness of ≈16 nm is transferred onto a gold substrate. The flake is characterized by micro‐Raman and nano‐FTIR spectroscopy. The Raman spectra show no difference between points on the flat surface and points on the wrinkles of the flake. Nano‐FTIR spectra, while comparable to conventional infrared spectra on the flat surface, show a strong change in the form of a second absorption peak appearing near a wrinkle in the flake. This second absorption peak shifts to higher wavenumber and becomes more intense as the probed spot gets closer to the wrinkle. This is consistent with the behavior of phonon polaritons when approaching the scattering point that is reflecting them.
{"title":"Phonon Polaritons Launched by Natural Boron Nitride Wrinkles Probed with Nano‐Fourier Transform Infrared Spectroscopy","authors":"Lukas Hertling, Dietrich R. T. Zahn","doi":"10.1002/pssb.202400201","DOIUrl":"https://doi.org/10.1002/pssb.202400201","url":null,"abstract":"Nano‐fourier transform infrared spectroscopy (FTIR) is a powerful tool to measure optical and electronic properties of materials at the nanoscale. It is especially useful for visualizing plasmon and phonon polaritons launched from edges of a sample or structures on top of it. Herein, an exfoliated hexagonal boron nitride flake with a thickness of ≈16 nm is transferred onto a gold substrate. The flake is characterized by micro‐Raman and nano‐FTIR spectroscopy. The Raman spectra show no difference between points on the flat surface and points on the wrinkles of the flake. Nano‐FTIR spectra, while comparable to conventional infrared spectra on the flat surface, show a strong change in the form of a second absorption peak appearing near a wrinkle in the flake. This second absorption peak shifts to higher wavenumber and becomes more intense as the probed spot gets closer to the wrinkle. This is consistent with the behavior of phonon polaritons when approaching the scattering point that is reflecting them.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"81 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lead halide perovskites, and their derivatives, are among the most promising photovoltaic materials for third generation solar cells. Despite the large number of available works on some of these materials, excitonic properties whose assessment has been challenging are less investigated. These include quantitative measures of excitonic properties variations with van der Waals (vdW) interactions. Consistent comparisons of how vdW interactions affect phononic and optical properties are also desirable. This work focuses on cubic phases of with X = Cl, Br, I, and MA = methylammonium, using density functional theory simulations including vdW interactions. These cause 30%–38% increase of absolute cohesive energies and 15%–37% reduction of ionic/vibrational contributions to static dielectric constants, along with 10%–29% reduction of exciton Bohr radii and 29%–107% increase of exciton binding energies. The effects on band gaps, frequency‐dependent dielectric functions, and exciton effective masses are less pronounced. Within the Mott–Wannier exciton model, the results suggest a trade‐off between photovoltaic performance and structure stability. The results can help assess stability, feasibility, and performance of hybrid photovoltaic materials.
卤化铅包晶石及其衍生物是第三代太阳能电池中最有前途的光伏材料之一。尽管对其中一些材料进行了大量研究，但对其激子特性的评估一直是个挑战，对这些特性的研究较少。其中包括对范德华（vdW）相互作用的激子特性变化的定量测量。我们还希望对范德华相互作用如何影响声子和光学特性进行一致的比较。这项工作的重点是利用包括 vdW 相互作用的密度泛函理论模拟 X = Cl、Br、I 和 MA = 甲基铵的立方相。这些相互作用导致绝对内聚能增加 30%-38%，离子/振动对静态介电常数的贡献减少 15%-37%，同时激子玻尔半径减少 10%-29%，激子结合能增加 29%-107%。对带隙、频率介电常数和激子有效质量的影响则不太明显。在莫特-万尼尔激子模型中，结果表明光电性能和结构稳定性之间存在权衡。这些结果有助于评估混合光伏材料的稳定性、可行性和性能。
{"title":"Excitonic Properties versus Structure Stability Trade‐Off in Halide Perovskite Photovoltaics Caused by van der Waals Interactions","authors":"Siddharth N. Rathod, Amir A. Farajian","doi":"10.1002/pssb.202400149","DOIUrl":"https://doi.org/10.1002/pssb.202400149","url":null,"abstract":"Lead halide perovskites, and their derivatives, are among the most promising photovoltaic materials for third generation solar cells. Despite the large number of available works on some of these materials, excitonic properties whose assessment has been challenging are less investigated. These include quantitative measures of excitonic properties variations with van der Waals (vdW) interactions. Consistent comparisons of how vdW interactions affect phononic and optical properties are also desirable. This work focuses on cubic phases of with X = Cl, Br, I, and MA = methylammonium, using density functional theory simulations including vdW interactions. These cause 30%–38% increase of absolute cohesive energies and 15%–37% reduction of ionic/vibrational contributions to static dielectric constants, along with 10%–29% reduction of exciton Bohr radii and 29%–107% increase of exciton binding energies. The effects on band gaps, frequency‐dependent dielectric functions, and exciton effective masses are less pronounced. Within the Mott–Wannier exciton model, the results suggest a trade‐off between photovoltaic performance and structure stability. The results can help assess stability, feasibility, and performance of hybrid photovoltaic materials.","PeriodicalId":20406,"journal":{"name":"Physica Status Solidi B-basic Solid State Physics","volume":"422 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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