Pub Date : 2012-07-12DOI: 10.1103/PhysRevB.86.165309
Anthony Burke, David J. Waddington, D. Carrad, R. Lyttleton, Hoe Hark Tan, Peter J. Reece, O. Klochan, A. Hamilton, A. Rai, D. Reuter, A. Wieck, A. Micolich
Gate instability and hysteresis in Si-doped p-type AlGaAs/GaAs heterostructures impedes the development of nanoscale hole devices, which are of interest for topics from quantum computing to novel spin physics. We report an extended study conducted using matched n-type and p-type heterostructures, with and without insulated gates, aimed at understanding the origin of the hysteresis. We show the hysteresis is not due to the inherent `leakiness' of gates on p-type heterostructures, as commonly believed. Instead, hysteresis arises from a combination of GaAs surface-state trapping and charge migration in the doping layer.
{"title":"The origin of gate hysteresis in p-type Si-doped AlGaAs/GaAs heterostructures","authors":"Anthony Burke, David J. Waddington, D. Carrad, R. Lyttleton, Hoe Hark Tan, Peter J. Reece, O. Klochan, A. Hamilton, A. Rai, D. Reuter, A. Wieck, A. Micolich","doi":"10.1103/PhysRevB.86.165309","DOIUrl":"https://doi.org/10.1103/PhysRevB.86.165309","url":null,"abstract":"Gate instability and hysteresis in Si-doped p-type AlGaAs/GaAs heterostructures impedes the development of nanoscale hole devices, which are of interest for topics from quantum computing to novel spin physics. We report an extended study conducted using matched n-type and p-type heterostructures, with and without insulated gates, aimed at understanding the origin of the hysteresis. We show the hysteresis is not due to the inherent `leakiness' of gates on p-type heterostructures, as commonly believed. Instead, hysteresis arises from a combination of GaAs surface-state trapping and charge migration in the doping layer.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122098033","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 : 1900-01-01DOI: 10.1109/COMMAD.2012.6472373
A. Bakar, Y. Lim, S. J. Wilson, K. Bertling, M. Fuentes, A. Rakić
This paper describes the proposed optical electrocardiograph (ECG) using self-mixing interferometer technique with a customized electro-optic phase modulator as the transducer. The surface ECG signals were recorded using commercially available electrodes demonstrating the feasibility of measuring the ECG signal using the SMI technique with its attendant benefits of intrinsic electrical safety and high level of EMI immunity.
{"title":"Optical electrocardiograph using self-mixing interferometer technique with a customized electro-optic phase modulator","authors":"A. Bakar, Y. Lim, S. J. Wilson, K. Bertling, M. Fuentes, A. Rakić","doi":"10.1109/COMMAD.2012.6472373","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472373","url":null,"abstract":"This paper describes the proposed optical electrocardiograph (ECG) using self-mixing interferometer technique with a customized electro-optic phase modulator as the transducer. The surface ECG signals were recorded using commercially available electrodes demonstrating the feasibility of measuring the ECG signal using the SMI technique with its attendant benefits of intrinsic electrical safety and high level of EMI immunity.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114352687","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 : 1900-01-01DOI: 10.1109/COMMAD.2012.6472369
K. Bertling, A. Rakić, Y. Yeow, C. J. O'brien, H. Domyo
Measurement of small-signal equivalent circuit parameters was carried out to estimate the RF performance of conventional inversion channel and depletion channel SOS MOSFET's. It was shown that the latter has significantly higher cutoff frequency fT attributed to electron mobility of the depletion channel.
{"title":"Comparison of the RF characteristics of inversion channel and depletion channel SOS MOSFETs","authors":"K. Bertling, A. Rakić, Y. Yeow, C. J. O'brien, H. Domyo","doi":"10.1109/COMMAD.2012.6472369","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472369","url":null,"abstract":"Measurement of small-signal equivalent circuit parameters was carried out to estimate the RF performance of conventional inversion channel and depletion channel SOS MOSFET's. It was shown that the latter has significantly higher cutoff frequency fT attributed to electron mobility of the depletion channel.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133439284","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 : 1900-01-01DOI: 10.1109/COMMAD.2012.6472382
Y. Lim, K. Bertling, P. Dean, A. Valavanis, R. Alhathlool, S. Khanna, D. Indjin, E. Linfield, A. Davies, S. J. Wilson, A. Rakić
Recently demonstrated self-mixing effect in terahertz quantum cascade lasers (QCL) opens new possibilities for detectorless sensing in this range of electromagnetic spectrum. In this paper we compare self-mixing signals obtained from variations in QCL terminal voltage against the signals obtained from variations in QCL radiated power monitored using a bolometer. We show that these two signals are equivalent allowing for the disposal of a conventional bulky and slow thermal detector.
{"title":"Self-mixing signals in terahertz lasers","authors":"Y. Lim, K. Bertling, P. Dean, A. Valavanis, R. Alhathlool, S. Khanna, D. Indjin, E. Linfield, A. Davies, S. J. Wilson, A. Rakić","doi":"10.1109/COMMAD.2012.6472382","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472382","url":null,"abstract":"Recently demonstrated self-mixing effect in terahertz quantum cascade lasers (QCL) opens new possibilities for detectorless sensing in this range of electromagnetic spectrum. In this paper we compare self-mixing signals obtained from variations in QCL terminal voltage against the signals obtained from variations in QCL radiated power monitored using a bolometer. We show that these two signals are equivalent allowing for the disposal of a conventional bulky and slow thermal detector.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124168881","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 : 1900-01-01DOI: 10.1109/COMMAD.2012.6472333
Z. Liao, H. Y. Xu, W. Sun, Y. Guo, L. Yang, Z. Chen, J. Zou, Z. Lu, P. P. Chen, W. Lu
To understand the growth mechanism and the effect of catalysts in growing III-V epitaxial nanowires, GaAs (111)B substrates with Au thin films were annealed in a molecular beam epitaxy (MBE) system. Scanning/transmission electron microscopy (SEM/TEM) investigations indicate that, during annealing, the Au catalysts were formed and affect significantly the surface morphology of the GaAs substrates.
{"title":"Effects of Au catalyst on GaAs (111)B surface during annealing","authors":"Z. Liao, H. Y. Xu, W. Sun, Y. Guo, L. Yang, Z. Chen, J. Zou, Z. Lu, P. P. Chen, W. Lu","doi":"10.1109/COMMAD.2012.6472333","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472333","url":null,"abstract":"To understand the growth mechanism and the effect of catalysts in growing III-V epitaxial nanowires, GaAs (111)B substrates with Au thin films were annealed in a molecular beam epitaxy (MBE) system. Scanning/transmission electron microscopy (SEM/TEM) investigations indicate that, during annealing, the Au catalysts were formed and affect significantly the surface morphology of the GaAs substrates.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129000834","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 : 1900-01-01DOI: 10.1109/COMMAD.2012.6472371
R. Kliese, Y. Lim, K. Bertling, A. Rakić
The self-mixing laser sensor makes compact, low-cost velocimetry sensing possible. In this work we describe a process for modelling the velocimetry signal that includes the dynamic speckle effect. We give results showing a good match between experimentally acquired signals and the model.
{"title":"Self-mixing laser velocimetry: A realistic model","authors":"R. Kliese, Y. Lim, K. Bertling, A. Rakić","doi":"10.1109/COMMAD.2012.6472371","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472371","url":null,"abstract":"The self-mixing laser sensor makes compact, low-cost velocimetry sensing possible. In this work we describe a process for modelling the velocimetry signal that includes the dynamic speckle effect. We give results showing a good match between experimentally acquired signals and the model.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129546971","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 : 1900-01-01DOI: 10.1109/COMMAD.2012.6472370
J. Gaynor, Y. Lim, K. Bertling, A. Rakić
This paper investigates the resolution and contrast in a near-infrared VCSEL based interferometric confocal microscope and proposes an architecture that can be readily applied in a range of bipolar and unipolar semiconductor lasers. Homodyning nature of the interferometric imaging technique helps overcome the problems related to weak scattered field while imaging nano-particles and low index-contrast objects.
{"title":"Towards a scanning laser confocal microscope using the self-mixing effect","authors":"J. Gaynor, Y. Lim, K. Bertling, A. Rakić","doi":"10.1109/COMMAD.2012.6472370","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472370","url":null,"abstract":"This paper investigates the resolution and contrast in a near-infrared VCSEL based interferometric confocal microscope and proposes an architecture that can be readily applied in a range of bipolar and unipolar semiconductor lasers. Homodyning nature of the interferometric imaging technique helps overcome the problems related to weak scattered field while imaging nano-particles and low index-contrast objects.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134314555","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 : 1900-01-01DOI: 10.1109/COMMAD.2012.6472336
J. Zou, Yong Wang, F. Xiu, Zuoming Zhao, K. Wang
In this study, the structural characteristics of GeMn diluted magnetic semiconductor (DMS) thin films grown by molecular beam epitaxy (MBE) with different growth conditions are summarised.
{"title":"Structural characteristics of GeMn diluted magnetic semiconductor nanostructures","authors":"J. Zou, Yong Wang, F. Xiu, Zuoming Zhao, K. Wang","doi":"10.1109/COMMAD.2012.6472336","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472336","url":null,"abstract":"In this study, the structural characteristics of GeMn diluted magnetic semiconductor (DMS) thin films grown by molecular beam epitaxy (MBE) with different growth conditions are summarised.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116498260","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 : 1900-01-01DOI: 10.1109/COMMAD.2012.6472345
H. Y. Xu, Y. Guo, Z. Liao, J. Zou, Q. Gao, H. Tan, C. Jagadish
To explore the growth mechanism and the effect of non-gold catalysts in growing III-V epitaxial nanowires, InAs nanowires were grown on GaAs(111)B substrates using annealed Pd thin film as catalyst. Through detailed scanning and transmission electron microscopy (SEM/TEM) characterisations, it is found that when the catalyst size is less than 50 nm (from annealing the Pd thin film), defect-free zinc-blende structured epitaxial InAs nanowires are grown along the <;110> directions with four {111} side-facets. The common nanowire/catalyst interface is found to be the unusual {113} planes of the nanowires.
{"title":"Growth of defect-free InAs nanowires using Pd catalyst","authors":"H. Y. Xu, Y. Guo, Z. Liao, J. Zou, Q. Gao, H. Tan, C. Jagadish","doi":"10.1109/COMMAD.2012.6472345","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472345","url":null,"abstract":"To explore the growth mechanism and the effect of non-gold catalysts in growing III-V epitaxial nanowires, InAs nanowires were grown on GaAs(111)B substrates using annealed Pd thin film as catalyst. Through detailed scanning and transmission electron microscopy (SEM/TEM) characterisations, it is found that when the catalyst size is less than 50 nm (from annealing the Pd thin film), defect-free zinc-blende structured epitaxial InAs nanowires are grown along the <;110> directions with four {111} side-facets. The common nanowire/catalyst interface is found to be the unusual {113} planes of the nanowires.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133807369","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 : 1900-01-01DOI: 10.1109/COMMAD.2012.6472403
W. Sun, Y. Guo, H. Y. Xu, Z. Liao, J. Zou, Q. Gao, H. Tan, C. Jagadish
In the growth of GaAsP nanowires on GaAs (001) substrates, it was found that the P concentrations in the nanowires and unintentional two-dimensional (2D) GaAsP layer are different. Possible explanations are given.
{"title":"Unequal P distribution in nanowires and the layer during the growth of GaAsP nanowires on GaAs","authors":"W. Sun, Y. Guo, H. Y. Xu, Z. Liao, J. Zou, Q. Gao, H. Tan, C. Jagadish","doi":"10.1109/COMMAD.2012.6472403","DOIUrl":"https://doi.org/10.1109/COMMAD.2012.6472403","url":null,"abstract":"In the growth of GaAsP nanowires on GaAs (001) substrates, it was found that the P concentrations in the nanowires and unintentional two-dimensional (2D) GaAsP layer are different. Possible explanations are given.","PeriodicalId":136573,"journal":{"name":"COMMAD 2012","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126084156","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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