Qingyue Li, Claire Deeb, Hélène Debregeas, J. Pelouard
We report the results of a study on the inductively coupled plasma (ICP) etching of InP at room temperature using Cl2 mixtures (Cl2/N2/H2). The impact of different process parameters, including the RF power, the ICP power, the ion-to-neutral ratio, and the chamber pressure, on the etched profile was investigated. The etch rate, selectivity, and anisotropy of the profile were depicted for each etching recipe. Two types of masks, such as SiO2 and AZ5214 photoresist, were used in this study. The etched InP feature showed a very smooth surface (rms as low as 0.5 nm) and a relatively fast etch rate of about 450 nm/min with both masks. By adjusting the etch process and depending on the used mask, we tuned the anisotropy from about 19° to 60°. A selectivity of around 4:1 and 1:1 was obtained with SiO2 and photoresist masks, respectively. These results demonstrate how altering the ICP process parameters could affect the etching characteristics and profile.
{"title":"Room temperature inductively coupled plasma etching of InP with Cl2 mixtures using SiO2 and photoresist masks","authors":"Qingyue Li, Claire Deeb, Hélène Debregeas, J. Pelouard","doi":"10.1116/6.0003295","DOIUrl":"https://doi.org/10.1116/6.0003295","url":null,"abstract":"We report the results of a study on the inductively coupled plasma (ICP) etching of InP at room temperature using Cl2 mixtures (Cl2/N2/H2). The impact of different process parameters, including the RF power, the ICP power, the ion-to-neutral ratio, and the chamber pressure, on the etched profile was investigated. The etch rate, selectivity, and anisotropy of the profile were depicted for each etching recipe. Two types of masks, such as SiO2 and AZ5214 photoresist, were used in this study. The etched InP feature showed a very smooth surface (rms as low as 0.5 nm) and a relatively fast etch rate of about 450 nm/min with both masks. By adjusting the etch process and depending on the used mask, we tuned the anisotropy from about 19° to 60°. A selectivity of around 4:1 and 1:1 was obtained with SiO2 and photoresist masks, respectively. These results demonstrate how altering the ICP process parameters could affect the etching characteristics and profile.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"50 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139777357","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}
Zhanyi Wang, Jingli Gong, Jian-Jun He, Lu Li, Rui Q. Yang, James A. Gupta
We report an investigation of V-coupled cavity interband cascade (IC) lasers (ICLs) emitting in the 3-μm wavelength range, employing various waveguide structures and coupler sizes. Type-II ICL devices with double-ridge waveguides exhibited wide tuning ranges exceeding 153 nm. Type-I ICL devices with deep-etched waveguides achieved single-mode emission with wavelength tunable over 100 nm at relatively high temperatures up to 250 K. All devices exhibited a side-mode suppression ratio higher than 30 dB. By comparing the performance of all devices with different sizes and configurations, a good tolerance against the structural parameter variations of the V-coupled cavity laser (VCCL) design is demonstrated, validating the advantages of the VCCL to achieve single-mode emission with wide tunability.
我们报告了对采用不同波导结构和耦合器尺寸、在 3-μm 波长范围内发射的 V 型耦合腔带间级联（IC）激光器（ICL）的研究。采用双脊波导的 II 型 ICL 器件显示出超过 153 nm 的宽调谐范围。采用深蚀刻波导的 I 型 ICL 器件实现了单模发射，在 250 K 的相对高温下波长可调超过 100 nm。通过比较不同尺寸和配置的所有器件的性能，证明了 V 型耦合腔激光器（VCCL）设计对结构参数变化的良好耐受性，验证了 VCCL 在实现单模发射和宽可调谐性方面的优势。
{"title":"Widely tunable single-mode interband cascade lasers based on V-coupled cavities and dependence on design parameters","authors":"Zhanyi Wang, Jingli Gong, Jian-Jun He, Lu Li, Rui Q. Yang, James A. Gupta","doi":"10.1116/6.0003376","DOIUrl":"https://doi.org/10.1116/6.0003376","url":null,"abstract":"We report an investigation of V-coupled cavity interband cascade (IC) lasers (ICLs) emitting in the 3-μm wavelength range, employing various waveguide structures and coupler sizes. Type-II ICL devices with double-ridge waveguides exhibited wide tuning ranges exceeding 153 nm. Type-I ICL devices with deep-etched waveguides achieved single-mode emission with wavelength tunable over 100 nm at relatively high temperatures up to 250 K. All devices exhibited a side-mode suppression ratio higher than 30 dB. By comparing the performance of all devices with different sizes and configurations, a good tolerance against the structural parameter variations of the V-coupled cavity laser (VCCL) design is demonstrated, validating the advantages of the VCCL to achieve single-mode emission with wide tunability.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":" 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139791467","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}
Zhanyi Wang, Jingli Gong, Jian-Jun He, Lu Li, Rui Q. Yang, James A. Gupta
We report an investigation of V-coupled cavity interband cascade (IC) lasers (ICLs) emitting in the 3-μm wavelength range, employing various waveguide structures and coupler sizes. Type-II ICL devices with double-ridge waveguides exhibited wide tuning ranges exceeding 153 nm. Type-I ICL devices with deep-etched waveguides achieved single-mode emission with wavelength tunable over 100 nm at relatively high temperatures up to 250 K. All devices exhibited a side-mode suppression ratio higher than 30 dB. By comparing the performance of all devices with different sizes and configurations, a good tolerance against the structural parameter variations of the V-coupled cavity laser (VCCL) design is demonstrated, validating the advantages of the VCCL to achieve single-mode emission with wide tunability.
我们报告了对采用不同波导结构和耦合器尺寸、在 3-μm 波长范围内发射的 V 型耦合腔带间级联（IC）激光器（ICL）的研究。采用双脊波导的 II 型 ICL 器件显示出超过 153 nm 的宽调谐范围。采用深蚀刻波导的 I 型 ICL 器件实现了单模发射，在 250 K 的相对高温下波长可调超过 100 nm。通过比较不同尺寸和配置的所有器件的性能，证明了 V 型耦合腔激光器（VCCL）设计对结构参数变化的良好耐受性，验证了 VCCL 在实现单模发射和宽可调谐性方面的优势。
{"title":"Widely tunable single-mode interband cascade lasers based on V-coupled cavities and dependence on design parameters","authors":"Zhanyi Wang, Jingli Gong, Jian-Jun He, Lu Li, Rui Q. Yang, James A. Gupta","doi":"10.1116/6.0003376","DOIUrl":"https://doi.org/10.1116/6.0003376","url":null,"abstract":"We report an investigation of V-coupled cavity interband cascade (IC) lasers (ICLs) emitting in the 3-μm wavelength range, employing various waveguide structures and coupler sizes. Type-II ICL devices with double-ridge waveguides exhibited wide tuning ranges exceeding 153 nm. Type-I ICL devices with deep-etched waveguides achieved single-mode emission with wavelength tunable over 100 nm at relatively high temperatures up to 250 K. All devices exhibited a side-mode suppression ratio higher than 30 dB. By comparing the performance of all devices with different sizes and configurations, a good tolerance against the structural parameter variations of the V-coupled cavity laser (VCCL) design is demonstrated, validating the advantages of the VCCL to achieve single-mode emission with wide tunability.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139851592","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}
Woo Jin Lee, Sang Ho Kim, Jun Sun Eom, Arnaud Caron
In this work, we use electrolytic copper foils as substrates for the deposition of graphene by chemical vapor deposition. We investigate the effects of preannealing conditions, methane injection time, and temperature to synthesize graphene with a similar quality as when grown on cold-rolled copper. We find that the electrolytic copper foil’s annealing conditions and CH4 injection temperature determine the quality of graphene.
{"title":"Comparing the properties and growth of graphene on electrolytic and rolled Cu foils by chemical vapor deposition","authors":"Woo Jin Lee, Sang Ho Kim, Jun Sun Eom, Arnaud Caron","doi":"10.1116/6.0002893","DOIUrl":"https://doi.org/10.1116/6.0002893","url":null,"abstract":"In this work, we use electrolytic copper foils as substrates for the deposition of graphene by chemical vapor deposition. We investigate the effects of preannealing conditions, methane injection time, and temperature to synthesize graphene with a similar quality as when grown on cold-rolled copper. We find that the electrolytic copper foil’s annealing conditions and CH4 injection temperature determine the quality of graphene.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"88 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139799850","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}
Woo Jin Lee, Sang Ho Kim, Jun Sun Eom, Arnaud Caron
In this work, we use electrolytic copper foils as substrates for the deposition of graphene by chemical vapor deposition. We investigate the effects of preannealing conditions, methane injection time, and temperature to synthesize graphene with a similar quality as when grown on cold-rolled copper. We find that the electrolytic copper foil’s annealing conditions and CH4 injection temperature determine the quality of graphene.
{"title":"Comparing the properties and growth of graphene on electrolytic and rolled Cu foils by chemical vapor deposition","authors":"Woo Jin Lee, Sang Ho Kim, Jun Sun Eom, Arnaud Caron","doi":"10.1116/6.0002893","DOIUrl":"https://doi.org/10.1116/6.0002893","url":null,"abstract":"In this work, we use electrolytic copper foils as substrates for the deposition of graphene by chemical vapor deposition. We investigate the effects of preannealing conditions, methane injection time, and temperature to synthesize graphene with a similar quality as when grown on cold-rolled copper. We find that the electrolytic copper foil’s annealing conditions and CH4 injection temperature determine the quality of graphene.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139859802","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}
Most cubic semiconductors have threefold degenerate p-bonding valence bands and nondegenerate s-antibonding conduction bands. This allows strong interband transitions from the valence to the conduction bands. On the other hand, intervalence band transitions within p-bonding orbitals in conventional p-type semiconductors are forbidden at k=0 and, therefore, weak, but observable. In gapless semiconductors, however, the s-antibonding band moves down between the split-off hole band and the valence band maximum due to the Darwin shift. This band arrangement makes them three-dimensional topological insulators. It also allows strong interband transitions from the s-antibonding valence band to the p-bonding bands, which have been observed in α-tin with Fourier-transform infrared spectroscopic ellipsometry [Carrasco et al., Appl. Phys. Lett. 113, 232104 (2018)]. This manuscript presents a theoretical description of such transitions applicable to many gapless semiconductors. This model is based on k→⋅p→ theory, degenerate carrier statistics, the excitonic Sommerfeld enhancement, and screening of the transitions by many-body effects. The impact of nonparabolic bands is approximated within Kane’s 8×8k→⋅p→-model by adjustments of the effective masses. This achieves agreement with experiments.
大多数立方半导体都有三重退化的 p 键价带和非退化的 s 反键导带。这使得从价带到导带的带间跃迁很强。另一方面，在传统的 p 型半导体中，p 键轨道内的带间转换在 k=0 时是被禁止的，因此转换很弱，但可以观察到。然而，在无间隙半导体中，由于达尔文偏移，s-反键带在空穴带和价带最大值之间向下移动。这种带排列使它们成为三维拓扑绝缘体。它还允许从 s 反键价带到 p 键带的强烈带间跃迁，傅立叶变换红外光谱椭偏仪已在α-锡中观察到这种跃迁[Carrasco 等人，Appl. Phys. Lett.本手稿介绍了适用于许多无间隙半导体的此类跃迁的理论描述。该模型基于 k⋅p→ 理论、变性载流子统计、激子索默费尔德增强以及多体效应对跃迁的屏蔽。在凯恩的 8×8k→⋅p→ 模型中，通过调整有效质量来近似考虑非抛物带的影响。这实现了与实验的一致。
{"title":"Excitonic effects in the optical absorption of gapless semiconductor α-tin near the direct bandgap","authors":"Stefan Zollner","doi":"10.1116/6.0003278","DOIUrl":"https://doi.org/10.1116/6.0003278","url":null,"abstract":"Most cubic semiconductors have threefold degenerate p-bonding valence bands and nondegenerate s-antibonding conduction bands. This allows strong interband transitions from the valence to the conduction bands. On the other hand, intervalence band transitions within p-bonding orbitals in conventional p-type semiconductors are forbidden at k=0 and, therefore, weak, but observable. In gapless semiconductors, however, the s-antibonding band moves down between the split-off hole band and the valence band maximum due to the Darwin shift. This band arrangement makes them three-dimensional topological insulators. It also allows strong interband transitions from the s-antibonding valence band to the p-bonding bands, which have been observed in α-tin with Fourier-transform infrared spectroscopic ellipsometry [Carrasco et al., Appl. Phys. Lett. 113, 232104 (2018)]. This manuscript presents a theoretical description of such transitions applicable to many gapless semiconductors. This model is based on k→⋅p→ theory, degenerate carrier statistics, the excitonic Sommerfeld enhancement, and screening of the transitions by many-body effects. The impact of nonparabolic bands is approximated within Kane’s 8×8k→⋅p→-model by adjustments of the effective masses. This achieves agreement with experiments.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"9 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139802848","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}
Polymeric residues and films of various thicknesses on the wafer backside and the edge frontside bevel and backside are known to cause substantial yield losses. An additional ex situ bevel etch step can clear away these buildups from the edge bevel area but not from the wafer backside. In this paper, we demonstrate a novel and innovative in situ pin-up plasma clean step that can effectively remove polymers from both the wafer backside and the edge bevel areas, eliminating the need for the bevel etch step. A physical analysis of blanket test wafers and patterned product wafers that have underwent the pin-up clean step in inductively coupled plasma and capacitively coupled plasma etch systems reveals that the pin-up clean step can reduce defect counts on product wafers and improve manufacturing cycle time and throughput by relaxing the queue time constraint.
{"title":"In situ plasma pin-up clean process for backside bevel polymer removal, defect reduction, and queue time relaxation","authors":"B. B. Ye, Ganquan Song, Jeff J. Ye","doi":"10.1116/6.0003300","DOIUrl":"https://doi.org/10.1116/6.0003300","url":null,"abstract":"Polymeric residues and films of various thicknesses on the wafer backside and the edge frontside bevel and backside are known to cause substantial yield losses. An additional ex situ bevel etch step can clear away these buildups from the edge bevel area but not from the wafer backside. In this paper, we demonstrate a novel and innovative in situ pin-up plasma clean step that can effectively remove polymers from both the wafer backside and the edge bevel areas, eliminating the need for the bevel etch step. A physical analysis of blanket test wafers and patterned product wafers that have underwent the pin-up clean step in inductively coupled plasma and capacitively coupled plasma etch systems reveals that the pin-up clean step can reduce defect counts on product wafers and improve manufacturing cycle time and throughput by relaxing the queue time constraint.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"22 38","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139803413","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}
Polymeric residues and films of various thicknesses on the wafer backside and the edge frontside bevel and backside are known to cause substantial yield losses. An additional ex situ bevel etch step can clear away these buildups from the edge bevel area but not from the wafer backside. In this paper, we demonstrate a novel and innovative in situ pin-up plasma clean step that can effectively remove polymers from both the wafer backside and the edge bevel areas, eliminating the need for the bevel etch step. A physical analysis of blanket test wafers and patterned product wafers that have underwent the pin-up clean step in inductively coupled plasma and capacitively coupled plasma etch systems reveals that the pin-up clean step can reduce defect counts on product wafers and improve manufacturing cycle time and throughput by relaxing the queue time constraint.
{"title":"In situ plasma pin-up clean process for backside bevel polymer removal, defect reduction, and queue time relaxation","authors":"B. B. Ye, Ganquan Song, Jeff J. Ye","doi":"10.1116/6.0003300","DOIUrl":"https://doi.org/10.1116/6.0003300","url":null,"abstract":"Polymeric residues and films of various thicknesses on the wafer backside and the edge frontside bevel and backside are known to cause substantial yield losses. An additional ex situ bevel etch step can clear away these buildups from the edge bevel area but not from the wafer backside. In this paper, we demonstrate a novel and innovative in situ pin-up plasma clean step that can effectively remove polymers from both the wafer backside and the edge bevel areas, eliminating the need for the bevel etch step. A physical analysis of blanket test wafers and patterned product wafers that have underwent the pin-up clean step in inductively coupled plasma and capacitively coupled plasma etch systems reveals that the pin-up clean step can reduce defect counts on product wafers and improve manufacturing cycle time and throughput by relaxing the queue time constraint.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"38 5-6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139863184","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}
Most cubic semiconductors have threefold degenerate p-bonding valence bands and nondegenerate s-antibonding conduction bands. This allows strong interband transitions from the valence to the conduction bands. On the other hand, intervalence band transitions within p-bonding orbitals in conventional p-type semiconductors are forbidden at k=0 and, therefore, weak, but observable. In gapless semiconductors, however, the s-antibonding band moves down between the split-off hole band and the valence band maximum due to the Darwin shift. This band arrangement makes them three-dimensional topological insulators. It also allows strong interband transitions from the s-antibonding valence band to the p-bonding bands, which have been observed in α-tin with Fourier-transform infrared spectroscopic ellipsometry [Carrasco et al., Appl. Phys. Lett. 113, 232104 (2018)]. This manuscript presents a theoretical description of such transitions applicable to many gapless semiconductors. This model is based on k→⋅p→ theory, degenerate carrier statistics, the excitonic Sommerfeld enhancement, and screening of the transitions by many-body effects. The impact of nonparabolic bands is approximated within Kane’s 8×8k→⋅p→-model by adjustments of the effective masses. This achieves agreement with experiments.
大多数立方半导体都有三重退化的 p 键价带和非退化的 s 反键导带。这使得从价带到导带的带间跃迁很强。另一方面，在传统的 p 型半导体中，p 键轨道内的带间转换在 k=0 时是被禁止的，因此转换很弱，但可以观察到。然而，在无间隙半导体中，由于达尔文偏移，s-反键带在空穴带和价带最大值之间向下移动。这种带排列使它们成为三维拓扑绝缘体。它还允许从 s 反键价带到 p 键带的强烈带间跃迁，傅立叶变换红外光谱椭偏仪已在α-锡中观察到这种跃迁[Carrasco 等人，Appl. Phys. Lett.本手稿介绍了适用于许多无间隙半导体的此类跃迁的理论描述。该模型基于 k⋅p→ 理论、变性载流子统计、激子索默费尔德增强以及多体效应对跃迁的屏蔽。在凯恩的 8×8k→⋅p→ 模型中，通过调整有效质量来近似考虑非抛物带的影响。这实现了与实验的一致。
{"title":"Excitonic effects in the optical absorption of gapless semiconductor α-tin near the direct bandgap","authors":"Stefan Zollner","doi":"10.1116/6.0003278","DOIUrl":"https://doi.org/10.1116/6.0003278","url":null,"abstract":"Most cubic semiconductors have threefold degenerate p-bonding valence bands and nondegenerate s-antibonding conduction bands. This allows strong interband transitions from the valence to the conduction bands. On the other hand, intervalence band transitions within p-bonding orbitals in conventional p-type semiconductors are forbidden at k=0 and, therefore, weak, but observable. In gapless semiconductors, however, the s-antibonding band moves down between the split-off hole band and the valence band maximum due to the Darwin shift. This band arrangement makes them three-dimensional topological insulators. It also allows strong interband transitions from the s-antibonding valence band to the p-bonding bands, which have been observed in α-tin with Fourier-transform infrared spectroscopic ellipsometry [Carrasco et al., Appl. Phys. Lett. 113, 232104 (2018)]. This manuscript presents a theoretical description of such transitions applicable to many gapless semiconductors. This model is based on k→⋅p→ theory, degenerate carrier statistics, the excitonic Sommerfeld enhancement, and screening of the transitions by many-body effects. The impact of nonparabolic bands is approximated within Kane’s 8×8k→⋅p→-model by adjustments of the effective masses. This achieves agreement with experiments.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"158 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139862750","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}
Optical properties of two-dimensional bilayer silicon have been explored at midinfrared wavelengths using density functional theory. In this work, progressive atomic structural deformation and the resultant variations in the optical properties of the bilayer silicon films were investigated under external in-plane strain. A phase transformation of the atomic structure has been observed at an applied in-plane tensile strain of 5.17%, at which the atomic lattice is changed from a low buckled to a buckle-free honeycomb structure. Evaluations of the optical properties were carried out by taking into account the inter- and intraband transitions. An abrupt change in the optical refraction index was observed at the phase transition. In addition, the buckle-free honeycomb structure presents a strain-resistive absorption edge pinned at 1.14 μm wavelength. Exceeding a strain threshold of 12.26% results in the development of both direct- and indirect-energy bandgap openings. The direct bandgap induced interband optical transitions, resulting in absorption peaks at midinfrared wavelengths and a drastic increase in the refraction index. Moreover, by adjusting the strain, the optical absorptions can be tuned in a wide range of wavelength at midinfrared from 1.5 to 11.5 μm.
{"title":"Strain-tuned optical properties of bilayer silicon at midinfrared wavelengths","authors":"K. Vishal, Z. Ji, Y. Zhuang","doi":"10.1116/6.0003202","DOIUrl":"https://doi.org/10.1116/6.0003202","url":null,"abstract":"Optical properties of two-dimensional bilayer silicon have been explored at midinfrared wavelengths using density functional theory. In this work, progressive atomic structural deformation and the resultant variations in the optical properties of the bilayer silicon films were investigated under external in-plane strain. A phase transformation of the atomic structure has been observed at an applied in-plane tensile strain of 5.17%, at which the atomic lattice is changed from a low buckled to a buckle-free honeycomb structure. Evaluations of the optical properties were carried out by taking into account the inter- and intraband transitions. An abrupt change in the optical refraction index was observed at the phase transition. In addition, the buckle-free honeycomb structure presents a strain-resistive absorption edge pinned at 1.14 μm wavelength. Exceeding a strain threshold of 12.26% results in the development of both direct- and indirect-energy bandgap openings. The direct bandgap induced interband optical transitions, resulting in absorption peaks at midinfrared wavelengths and a drastic increase in the refraction index. Moreover, by adjusting the strain, the optical absorptions can be tuned in a wide range of wavelength at midinfrared from 1.5 to 11.5 μm.","PeriodicalId":282302,"journal":{"name":"Journal of Vacuum Science & Technology B","volume":"38 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139809705","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}
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