Robert Knuesel - Academia.edu (original) (raw)
Papers by Robert Knuesel
We report on recent progress in the directed self-assembly of discrete inorganic semiconductor de... more We report on recent progress in the directed self-assembly of discrete inorganic semiconductor device components. Different from prior research, the goal is to enable the integration of increasingly small dies while supporting unique-angle orientation and contact pad registration. The process is based on the reduction of surface free energy between liquid solder coated areas on the substrate and metal-coated binding sites on the semiconductor dies. Recent advances include flip-chip assembly with unique angular orientation accomplished using “twoelement” docking sites that contain pedestals that act as chaperones for the solder directed assembly to take place. The scale reduction to 20 µm sized components involves the use of a liquid-liquid interface to concentrate component delivery and speed up the self-assembly process to prevent oxidative dissolution of the solder sites prior to completion.
This article reports a new integration approach to produce arrays of ZnO microcrystals for optoel... more This article reports a new integration approach to produce arrays of ZnO microcrystals for optoelectronic and photovoltaic applications. Demonstrated applications are n-ZnO/p-GaN heterojunction LEDs and photovoltaic cells. The integration process uses an oxygen plasma treatment in combination with a photoresist pattern on magnesium doped GaN substrates to define a narrow sub-100 nm width nucleation region. Nucleation is followed by lateral epitaxial overgrowth producing single crystal disks of ZnO with desired size over 2 in. wafers. The process provides control over the dimensions (<1 % STD) and the location (0.7 % STD pitch variation) of the ZnO crystals. The quality of the patterned ZnO is high; the commonly observed defect related emission in the electroluminescence spectra is completely suppressed, and a single near-band-edge UV peak is observed. ZnO is a promising material for exciton-based opto-electronic devices including light emitting (LED) and laser diodes because of i...
This proceeding reviews recent progress in fluidic surface-tension-directed self-assembly involvi... more This proceeding reviews recent progress in fluidic surface-tension-directed self-assembly involving liquid solder which has been applied to the self-packaging and self-mounting of discrete inorganic semiconductor device components at different length scales producing electrically interconnected devices and systems. Results included flip chip self-assembly with unique angular orientation and contact pad registration, parallel packaging and encapsulation, and the programmable self-mounting of various types of components ranging from phototransistors, to LEDs, to photovoltaic cells. We discuss recent challenges in extending the minimal component size below the 100 μm barrier where prior component delivery and agitation concepts have not worked. A new delivery system is presented to concentrate and effectively introduce the components which involves a liquid-liquid interface and energy cascade that drives the assembly process forward yielding a conveyor like assembly process. Recent app...
We report on recent progress in the directed selfassembly of discrete inorganic semiconductor dev... more We report on recent progress in the directed selfassembly of discrete inorganic semiconductor device components. Different from prior research, the goal is to enable the integration of increasingly small dies while supporting unique-angle orientation and contact pad registration. The process is based on the reduction of surface free energy between liquid solder coated areas on the substrate and metal-coated binding sites on the semiconductor dies. Recent advances include flip-chip assembly with unique angular orientation accomplished using “two-element” docking sites that contain pedestals that act as chaperones for the solder directed assembly to take place. The scale reduction to 20 μm sized components involves the use of a liquid-liquid interface to concentrate component delivery and speed up the self-assembly process to prevent oxidative dissolution of the solder sites prior to completion.
ACM Transactions on Accessible Computing (TACCESS), 2020
This article first reviews the pros and cons of current accessible indoor navigation systems and ... more This article first reviews the pros and cons of current accessible indoor navigation systems and then describes a study using commercial smart devices to navigate routes through a complex building. Our interest was in comparing performance when using real-time narrative descriptions (system-aided condition) vs. a memory-based condition where the same narrative information was only provided to users from the route's origin. We tested two groups of blind and visually impaired (BVI) users, including people above and below 60 years of age, as well as a third sighted control group. Evaluating older BVI participants is important, as the majority of vision loss is age-related, yet navigation performance using access technology is rarely studied with this demographic. Behavioral results demonstrated that access to real-time (system-aided) information led to better navigation accuracy and greater confidence by blind users compared to the information-matched memory condition. Performance ...
MRS Proceedings, 2009
This proceeding discusses recent progress on engineered fluidic surface-tension-directed self-ass... more This proceeding discusses recent progress on engineered fluidic surface-tension-directed self-assembly involving liquid solder. The process is applied to the assembly of discrete inorganic semiconductor device components at different length scales producing electrically interconnected devices and systems. Prior results include assembly with unique angular orientation and contact pad registration, parallel packaging, and the programmable assembly of various types of light emitting diodes. Recent progress on the scaling of the minimal die size from 300 to 30 μm is discussed which required the development of a new delivery system to concentrate and effectively introduce the components to solder-based receptors. Specifically, components are pre-oriented at a liquid-air or liquid-liquid interface and transferred onto the solder based receptors using a dynamic contact angle with a dipping process. Recent applications include the tiling of curved and 3D surfaces with single crystal semicon...
Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2006
To explore the efficacy of using a far infrared thermal camera with a haptic display to assist bl... more To explore the efficacy of using a far infrared thermal camera with a haptic display to assist blind people in identifying humans, we performed experiments with a prototype device on five low-vision (functionally blind) subjects. Infrared allows for easy detection of human shape due to typically high contrast in temperatures from a person against their surrounding environment. Infrared cameras can
We report on recent progress in the directed self-assembly of discrete inorganic semiconductor de... more We report on recent progress in the directed self-assembly of discrete inorganic semiconductor device components. Different from prior research, the goal is to enable the integration of increasingly small dies while supporting unique-angle orientation and contact pad registration. The process is based on the reduction of surface free energy between liquid solder coated areas on the substrate and metal-coated binding sites on the semiconductor dies. Recent advances include flip-chip assembly with unique angular orientation accomplished using "twoelement" docking sites that contain pedestals that act as chaperones for the solder directed assembly to take place. The scale reduction to 20 µm sized components involves the use of a liquid-liquid interface to concentrate component delivery and speed up the self-assembly process to prevent oxidative dissolution of the solder sites prior to completion.
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015
Telecoils in hearing aids serve a dual purpose: to enhance telephone conversation and enable hear... more Telecoils in hearing aids serve a dual purpose: to enhance telephone conversation and enable hearing aids to serve as a wireless interface for public audio broadcasts. When broadcasting audio signals, the signal is transmitted to the telecoil sensor (a magnetic field sensor located in the hearing aid) via magnetic energy from an induction wire loop located near the listener. This induction loop can be a small assembly located in the handset of the telephone or a large wire loop within a public venue like a theatre. Current hearing aids detect the magnetic signal using a single telecoil. If the telecoil is not aligned with the magnetic field, the strength of the detected signal is diminished. Unfortunately, public induction loops and telephone handsets seldom share a common alignment to the hearing aid, leading to sub-optimal performance by one or both in hearing aids available today. In this research, a prototype behind-the-ear (BTE) hearing aid with tri-axial telecoils was developed and DSP algorithms to process and combine the three signals were developed. The resulting hearing aid was evaluated in a human trial and provided better performance than a similar quality conventional telecoil hearing aid.
We report on recent progress in the directed self-assembly of discrete inorganic semiconductor de... more We report on recent progress in the directed self-assembly of discrete inorganic semiconductor device components. Different from prior research, the goal is to enable the integration of increasingly small dies while supporting unique-angle orientation and contact pad registration. The process is based on the reduction of surface free energy between liquid solder coated areas on the substrate and metal-coated binding sites on the semiconductor dies. Recent advances include flip-chip assembly with unique angular orientation accomplished using “twoelement” docking sites that contain pedestals that act as chaperones for the solder directed assembly to take place. The scale reduction to 20 µm sized components involves the use of a liquid-liquid interface to concentrate component delivery and speed up the self-assembly process to prevent oxidative dissolution of the solder sites prior to completion.
This article reports a new integration approach to produce arrays of ZnO microcrystals for optoel... more This article reports a new integration approach to produce arrays of ZnO microcrystals for optoelectronic and photovoltaic applications. Demonstrated applications are n-ZnO/p-GaN heterojunction LEDs and photovoltaic cells. The integration process uses an oxygen plasma treatment in combination with a photoresist pattern on magnesium doped GaN substrates to define a narrow sub-100 nm width nucleation region. Nucleation is followed by lateral epitaxial overgrowth producing single crystal disks of ZnO with desired size over 2 in. wafers. The process provides control over the dimensions (<1 % STD) and the location (0.7 % STD pitch variation) of the ZnO crystals. The quality of the patterned ZnO is high; the commonly observed defect related emission in the electroluminescence spectra is completely suppressed, and a single near-band-edge UV peak is observed. ZnO is a promising material for exciton-based opto-electronic devices including light emitting (LED) and laser diodes because of i...
This proceeding reviews recent progress in fluidic surface-tension-directed self-assembly involvi... more This proceeding reviews recent progress in fluidic surface-tension-directed self-assembly involving liquid solder which has been applied to the self-packaging and self-mounting of discrete inorganic semiconductor device components at different length scales producing electrically interconnected devices and systems. Results included flip chip self-assembly with unique angular orientation and contact pad registration, parallel packaging and encapsulation, and the programmable self-mounting of various types of components ranging from phototransistors, to LEDs, to photovoltaic cells. We discuss recent challenges in extending the minimal component size below the 100 μm barrier where prior component delivery and agitation concepts have not worked. A new delivery system is presented to concentrate and effectively introduce the components which involves a liquid-liquid interface and energy cascade that drives the assembly process forward yielding a conveyor like assembly process. Recent app...
We report on recent progress in the directed selfassembly of discrete inorganic semiconductor dev... more We report on recent progress in the directed selfassembly of discrete inorganic semiconductor device components. Different from prior research, the goal is to enable the integration of increasingly small dies while supporting unique-angle orientation and contact pad registration. The process is based on the reduction of surface free energy between liquid solder coated areas on the substrate and metal-coated binding sites on the semiconductor dies. Recent advances include flip-chip assembly with unique angular orientation accomplished using “two-element” docking sites that contain pedestals that act as chaperones for the solder directed assembly to take place. The scale reduction to 20 μm sized components involves the use of a liquid-liquid interface to concentrate component delivery and speed up the self-assembly process to prevent oxidative dissolution of the solder sites prior to completion.
ACM Transactions on Accessible Computing (TACCESS), 2020
This article first reviews the pros and cons of current accessible indoor navigation systems and ... more This article first reviews the pros and cons of current accessible indoor navigation systems and then describes a study using commercial smart devices to navigate routes through a complex building. Our interest was in comparing performance when using real-time narrative descriptions (system-aided condition) vs. a memory-based condition where the same narrative information was only provided to users from the route's origin. We tested two groups of blind and visually impaired (BVI) users, including people above and below 60 years of age, as well as a third sighted control group. Evaluating older BVI participants is important, as the majority of vision loss is age-related, yet navigation performance using access technology is rarely studied with this demographic. Behavioral results demonstrated that access to real-time (system-aided) information led to better navigation accuracy and greater confidence by blind users compared to the information-matched memory condition. Performance ...
MRS Proceedings, 2009
This proceeding discusses recent progress on engineered fluidic surface-tension-directed self-ass... more This proceeding discusses recent progress on engineered fluidic surface-tension-directed self-assembly involving liquid solder. The process is applied to the assembly of discrete inorganic semiconductor device components at different length scales producing electrically interconnected devices and systems. Prior results include assembly with unique angular orientation and contact pad registration, parallel packaging, and the programmable assembly of various types of light emitting diodes. Recent progress on the scaling of the minimal die size from 300 to 30 μm is discussed which required the development of a new delivery system to concentrate and effectively introduce the components to solder-based receptors. Specifically, components are pre-oriented at a liquid-air or liquid-liquid interface and transferred onto the solder based receptors using a dynamic contact angle with a dipping process. Recent applications include the tiling of curved and 3D surfaces with single crystal semicon...
Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2006
To explore the efficacy of using a far infrared thermal camera with a haptic display to assist bl... more To explore the efficacy of using a far infrared thermal camera with a haptic display to assist blind people in identifying humans, we performed experiments with a prototype device on five low-vision (functionally blind) subjects. Infrared allows for easy detection of human shape due to typically high contrast in temperatures from a person against their surrounding environment. Infrared cameras can
We report on recent progress in the directed self-assembly of discrete inorganic semiconductor de... more We report on recent progress in the directed self-assembly of discrete inorganic semiconductor device components. Different from prior research, the goal is to enable the integration of increasingly small dies while supporting unique-angle orientation and contact pad registration. The process is based on the reduction of surface free energy between liquid solder coated areas on the substrate and metal-coated binding sites on the semiconductor dies. Recent advances include flip-chip assembly with unique angular orientation accomplished using "twoelement" docking sites that contain pedestals that act as chaperones for the solder directed assembly to take place. The scale reduction to 20 µm sized components involves the use of a liquid-liquid interface to concentrate component delivery and speed up the self-assembly process to prevent oxidative dissolution of the solder sites prior to completion.
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015
Telecoils in hearing aids serve a dual purpose: to enhance telephone conversation and enable hear... more Telecoils in hearing aids serve a dual purpose: to enhance telephone conversation and enable hearing aids to serve as a wireless interface for public audio broadcasts. When broadcasting audio signals, the signal is transmitted to the telecoil sensor (a magnetic field sensor located in the hearing aid) via magnetic energy from an induction wire loop located near the listener. This induction loop can be a small assembly located in the handset of the telephone or a large wire loop within a public venue like a theatre. Current hearing aids detect the magnetic signal using a single telecoil. If the telecoil is not aligned with the magnetic field, the strength of the detected signal is diminished. Unfortunately, public induction loops and telephone handsets seldom share a common alignment to the hearing aid, leading to sub-optimal performance by one or both in hearing aids available today. In this research, a prototype behind-the-ear (BTE) hearing aid with tri-axial telecoils was developed and DSP algorithms to process and combine the three signals were developed. The resulting hearing aid was evaluated in a human trial and provided better performance than a similar quality conventional telecoil hearing aid.