Pub Date : 2012-12-01DOI: 10.1109/COMMAD.2012.6472431
H. Kala, G. Umana-Membreno, J. Antoszewski, Z. Ye, W. D. Hu, R. Ding, X. Chen, L. He, J. Dell, L. Faraone
Electron transport in n-type HgCdTe realised by Boron ion-implantation and inductively-coupled-plasma reactive-ion etching (ICP-RIE) of vacancy doped p-type HgCdTe has been investigated by employing variable magnetic field Hall-effect and resistivity measurements, coupled with high resolution mobility spectrum analysis (HR-MSA). Electron mobilities were found to be significantly higher in the ICP-RIE type-converted sample than in the ion-implanted sample, suggesting that type-conversion mechanisms in the two samples are significantly different.
{"title":"Mobility spectrum analysis of p-to-n type converted vacancy doped HgCdTe","authors":"H. Kala, G. Umana-Membreno, J. Antoszewski, Z. Ye, W. D. Hu, R. Ding, X. Chen, L. He, J. Dell, L. Faraone","doi":"10.1109/COMMAD.2012.6472431","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472431","url":null,"abstract":"Electron transport in n-type HgCdTe realised by Boron ion-implantation and inductively-coupled-plasma reactive-ion etching (ICP-RIE) of vacancy doped p-type HgCdTe has been investigated by employing variable magnetic field Hall-effect and resistivity measurements, coupled with high resolution mobility spectrum analysis (HR-MSA). Electron mobilities were found to be significantly higher in the ICP-RIE type-converted sample than in the ion-implanted sample, suggesting that type-conversion mechanisms in the two samples are significantly different.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134257580","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}
Pub Date : 2012-12-01DOI: 10.1109/COMMAD.2012.6472408
T. James, T. Davis, A. Roberts
Optical antennas have garnered much interest from the optics community for their ability to manipulate light below the diffraction limit of conventional optics. This relatively new capability to transform light at a sub-wavelength scale has been applied to quantum source enhancement, infrared detection and solar cell design. This work aims to expand upon the range of optical antennas presented in literature by exploiting the rich array of well-known radio-frequency (RF) antenna designs and applying them to the optical spectral region, for the enhancement of quantum emitters.
{"title":"Meters to nanometers; RF antennas for optics","authors":"T. James, T. Davis, A. Roberts","doi":"10.1109/COMMAD.2012.6472408","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472408","url":null,"abstract":"Optical antennas have garnered much interest from the optics community for their ability to manipulate light below the diffraction limit of conventional optics. This relatively new capability to transform light at a sub-wavelength scale has been applied to quantum source enhancement, infrared detection and solar cell design. This work aims to expand upon the range of optical antennas presented in literature by exploiting the rich array of well-known radio-frequency (RF) antenna designs and applying them to the optical spectral region, for the enhancement of quantum emitters.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127808728","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}
Pub Date : 2012-12-01DOI: 10.1109/COMMAD.2012.6472402
R. Gore, K. K. Lee, M. Ashokkumar, J. McCallum
We report on the growth of ZnO nanowires using two distinctive methods; sonochemistry and hydrothermal growth. The dimensions of the nanowires were varied by changing the concentration of the solution, growth time and volume of the solution. During growth by sonification, we were also able to alter the power supplied to the solution and the dimensions of the sonicator tip. The nanowires produced were then imaged using Scanning Electron Microscopy (SEM) and optical microscopy. We aim to create nanowires with dimensions suitable for the fabrication of ZnO nanowire transistor.
{"title":"Sonochemistry and hydrothermal pathways to the fabrication of ZnO nanowire transistors","authors":"R. Gore, K. K. Lee, M. Ashokkumar, J. McCallum","doi":"10.1109/COMMAD.2012.6472402","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472402","url":null,"abstract":"We report on the growth of ZnO nanowires using two distinctive methods; sonochemistry and hydrothermal growth. The dimensions of the nanowires were varied by changing the concentration of the solution, growth time and volume of the solution. During growth by sonification, we were also able to alter the power supplied to the solution and the dimensions of the sonicator tip. The nanowires produced were then imaged using Scanning Electron Microscopy (SEM) and optical microscopy. We aim to create nanowires with dimensions suitable for the fabrication of ZnO nanowire transistor.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114851646","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}
Pub Date : 2012-12-01DOI: 10.1109/COMMAD.2012.6472439
K. S. Chan, J. Ye, P. Parkinson, E. Monakhov, K. M. Johansen, L. Vines, B. Svensson, C. Jagadish, J. Wong-Leung
ZnO is a wide bandgap semiconductor with huge potential to fabricate optoelectronic devices operating in the UV region. However, it is still not possible to achieve p-type ZnO, with hydrogen suggested to be a shallow donor that contributes significantly to the n-type conductivity in as grown ZnO. A better understanding on the role of H in ZnO is needed to realise p-type doping in ZnO. In this research, we utilised multiple structural and optical techniques to study the effects caused by H implantation in ZnO. The H implanted region in single crystal ZnO substrate was characterised by X-Ray diffraction, photoluminescence spectroscopy, secondary ion mass spectroscopy and transmission electron microscopy. XRD results show that H implantation created deformed layers with strain increasing linearly with implantation dose. A blue shift is also observed from the UV photoluminescence emission of the H implanted ZnO.
{"title":"Structural and optical properties of H implanted ZnO","authors":"K. S. Chan, J. Ye, P. Parkinson, E. Monakhov, K. M. Johansen, L. Vines, B. Svensson, C. Jagadish, J. Wong-Leung","doi":"10.1109/COMMAD.2012.6472439","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472439","url":null,"abstract":"ZnO is a wide bandgap semiconductor with huge potential to fabricate optoelectronic devices operating in the UV region. However, it is still not possible to achieve p-type ZnO, with hydrogen suggested to be a shallow donor that contributes significantly to the n-type conductivity in as grown ZnO. A better understanding on the role of H in ZnO is needed to realise p-type doping in ZnO. In this research, we utilised multiple structural and optical techniques to study the effects caused by H implantation in ZnO. The H implanted region in single crystal ZnO substrate was characterised by X-Ray diffraction, photoluminescence spectroscopy, secondary ion mass spectroscopy and transmission electron microscopy. XRD results show that H implantation created deformed layers with strain increasing linearly with implantation dose. A blue shift is also observed from the UV photoluminescence emission of the H implanted ZnO.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128406152","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}
Pub Date : 2012-12-01DOI: 10.1109/COMMAD.2012.6472417
K. K. Lee, Y. Li
In this study, we modified single-walled carbon nanotubes (SWCNTs) by CHF3 plasma generated by reactive-ion etching (RIE) reactor. X-ray photo-electron spectroscopy (XPS) indicated fluorine atoms were attached to the side wall of CNTs. Static contact angle (CA) measurements indicated a very significant increase in the water contact angle from 65° for pristine CNTs to 170° for the doped SWCNTs.
{"title":"Fluorination of single-walled carbon nanotubes via CHF3 plasma","authors":"K. K. Lee, Y. Li","doi":"10.1109/COMMAD.2012.6472417","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472417","url":null,"abstract":"In this study, we modified single-walled carbon nanotubes (SWCNTs) by CHF3 plasma generated by reactive-ion etching (RIE) reactor. X-ray photo-electron spectroscopy (XPS) indicated fluorine atoms were attached to the side wall of CNTs. Static contact angle (CA) measurements indicated a very significant increase in the water contact angle from 65° for pristine CNTs to 170° for the doped SWCNTs.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122494012","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}
Pub Date : 2012-12-01DOI: 10.1109/COMMAD.2012.6472432
A. Burke, K. Storm, D. Carrad, G. Nylund, S. Svensson, O. Klochan, A. Hamilton, I. Farrer, D. Ritchie, H. Linke, L. Samuelson, A. Micolich
Electrostatically gated AlGaAs/GaAs quantum wires and InAs nanowires are two common platforms for studying 1D electron physics. Quantum wires are typically defined using a splitgate structure on an AlGaAs/GaAs heterostructure. Nanowires are typically gated from below by a heavily doped Si substrate. The level of control is limited in these heavily-studied, traditional device designs. Advancements in nanofabrication make it possible to implement more sophisticated gating schemes, enabling improved control over 1D devices. We will discuss our recent work on 1D electron devices with more advanced density control. We start firstly with the possibility of engineering the g-factor in top-gated quantum wires for spintronics applications [1], and then discuss our work on using wrap-gates to improve density control in InAs nanowires.
{"title":"“You need another gate, mate”: g-factor engineering in quantum wires and wrap-gated nanowires","authors":"A. Burke, K. Storm, D. Carrad, G. Nylund, S. Svensson, O. Klochan, A. Hamilton, I. Farrer, D. Ritchie, H. Linke, L. Samuelson, A. Micolich","doi":"10.1109/COMMAD.2012.6472432","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472432","url":null,"abstract":"Electrostatically gated AlGaAs/GaAs quantum wires and InAs nanowires are two common platforms for studying 1D electron physics. Quantum wires are typically defined using a splitgate structure on an AlGaAs/GaAs heterostructure. Nanowires are typically gated from below by a heavily doped Si substrate. The level of control is limited in these heavily-studied, traditional device designs. Advancements in nanofabrication make it possible to implement more sophisticated gating schemes, enabling improved control over 1D devices. We will discuss our recent work on 1D electron devices with more advanced density control. We start firstly with the possibility of engineering the g-factor in top-gated quantum wires for spintronics applications [1], and then discuss our work on using wrap-gates to improve density control in InAs nanowires.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123920309","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}
Pub Date : 2012-12-01DOI: 10.1109/COMMAD.2012.6472357
A. See, I. Pilgrim, B. Scannell, R. Montgomery, O. Klochan, A. Burke, M. Aagesen, P. Lindelof, I. Farrer, D. Ritchie, A. Hamilton, R. P. Taylor, A. Micolich
Disorder increasingly affects performance as electronic devices are reduced in size. The ionized dopants used to populate a device with electrons are particularly problematic, leading to unpredictable changes in the behaviour of devices such as quantum dots each time they are cooled for use. We show that a quantum dot can be used as a highly sensitive probe of changes in disorder potential and that, by removing the ionized dopants and populating the dot electrostatically, its electronic properties become reproducible with high fidelity after thermal cycling to room temperature. Our work demonstrates that the disorder potential has a significant, perhaps even dominant, influence on the electron dynamics, with important implications for `ballistic' transport in quantum dots.
{"title":"The influence of small-angle scattering on ballistic transport in quantum dots","authors":"A. See, I. Pilgrim, B. Scannell, R. Montgomery, O. Klochan, A. Burke, M. Aagesen, P. Lindelof, I. Farrer, D. Ritchie, A. Hamilton, R. P. Taylor, A. Micolich","doi":"10.1109/COMMAD.2012.6472357","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472357","url":null,"abstract":"Disorder increasingly affects performance as electronic devices are reduced in size. The ionized dopants used to populate a device with electrons are particularly problematic, leading to unpredictable changes in the behaviour of devices such as quantum dots each time they are cooled for use. We show that a quantum dot can be used as a highly sensitive probe of changes in disorder potential and that, by removing the ionized dopants and populating the dot electrostatically, its electronic properties become reproducible with high fidelity after thermal cycling to room temperature. Our work demonstrates that the disorder potential has a significant, perhaps even dominant, influence on the electron dynamics, with important implications for `ballistic' transport in quantum dots.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117341856","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}
Pub Date : 2012-12-01DOI: 10.1109/COMMAD.2012.6472366
B. Cheah, A. Keating, J. Dell
Laminar flow assisted wet etching has been employed to control the sacrificial layer etch progression during the release of silicon nitride (SiNx) microbeams, on a porous silicon (PS) sacrificial layer. A removable 3-inlet polydi-methylsiloxane (PDMS) microfluidic cassette allowed different fluids to be passed over the sample surface to generate a fluid mask. In contrast to solid masking, microfluidic devices can provide non-homogeneous etching conditions which can be controlled in real-time. In this work device input flow rates were altered during the etch, allowing specific surfaces to be exposed to etchant, resulting in beams with asymmetric anchor configurations.
{"title":"Tailoring anchor shape during release of MEMS microbeams using microfluidic flow","authors":"B. Cheah, A. Keating, J. Dell","doi":"10.1109/COMMAD.2012.6472366","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472366","url":null,"abstract":"Laminar flow assisted wet etching has been employed to control the sacrificial layer etch progression during the release of silicon nitride (SiNx) microbeams, on a porous silicon (PS) sacrificial layer. A removable 3-inlet polydi-methylsiloxane (PDMS) microfluidic cassette allowed different fluids to be passed over the sample surface to generate a fluid mask. In contrast to solid masking, microfluidic devices can provide non-homogeneous etching conditions which can be controlled in real-time. In this work device input flow rates were altered during the etch, allowing specific surfaces to be exposed to etchant, resulting in beams with asymmetric anchor configurations.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"237 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121629629","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}
Pub Date : 2012-12-01DOI: 10.1109/COMMAD.2012.6472433
J. Hsia, C. Shih
This work numerically examines the corner and short-channel effects in dopant segregated Schottky barrier MOSFETs (DS-SBMOS) with recessed channel. The recessed channel suppresses effectively the short-channel effect in the DS-SBMOS devices, whereas the recessed channel and oxide corners leads to a lower on-state current and worse on-off switching. The recessed depth plays the key role to optimize the on-current and subthreshold swing in the recessed channel DS-SBMOS.
{"title":"Corner and short-channel effects in recessed channel dopant segregated Schottky barrier MOSFETs","authors":"J. Hsia, C. Shih","doi":"10.1109/COMMAD.2012.6472433","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472433","url":null,"abstract":"This work numerically examines the corner and short-channel effects in dopant segregated Schottky barrier MOSFETs (DS-SBMOS) with recessed channel. The recessed channel suppresses effectively the short-channel effect in the DS-SBMOS devices, whereas the recessed channel and oxide corners leads to a lower on-state current and worse on-off switching. The recessed depth plays the key role to optimize the on-current and subthreshold swing in the recessed channel DS-SBMOS.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116981763","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}
Pub Date : 2012-12-01DOI: 10.1109/COMMAD.2012.6472340
D. Strukov
This paper is a brief overview of hybrid CMOS/memristor circuits and their applications for digital memories, programmable logic, and artificial neuromorphic networks.
本文简要介绍了CMOS/忆阻器混合电路及其在数字存储器、可编程逻辑和人工神经形态网络中的应用。
{"title":"3D hybrid CMOS/memristor circuits: Basic principle and prospective applications","authors":"D. Strukov","doi":"10.1109/COMMAD.2012.6472340","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472340","url":null,"abstract":"This paper is a brief overview of hybrid CMOS/memristor circuits and their applications for digital memories, programmable logic, and artificial neuromorphic networks.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131660770","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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