Abstract:
The disclosed technology generally relates to preparing two-dimensional material layers, and more particularly to releasing a graphene layer from a template substrate. According to an aspect, a method of releasing a graphene layer includes providing a template substrate on which the graphene layer is provided, the method comprising: subjecting the graphene layer and the template substrate to a water treatment by soaking the graphene layer and the template substrate in water such that water is intercalated between the template substrate and the graphene layer; and subjecting the graphene layer and the template substrate to a delamination process, thereby releasing the graphene layer from the template substrate.
Abstract:
This present application relates to a system for delivering megasonic energy to a liquid, involving one or more megasonic transducers, each transducer having a single operating frequency within an ultrasound bandwidth and comprising two or more groups of piezoelectric elements arranged in one or more rows, and a megasonic generator means for driving the one or more transducers at frequencies within the bandwidth, the generator means being adapted for changing the voltage applied to each group of piezoelectric elements so as to achieve substantially the same maximum acoustic pressure for each group of piezoelectric elements. The generator means and transducers being constructed and arranged so as to produce ultrasound within the liquid. Such a system may be part of an apparatus for cleaning a surface of an article such as a semiconductor wafer or a medical implant.
Abstract:
Disclosed are systems and methods for cleaning semiconductor substrates, wherein a nucleation structure having nucleation sites is mounted facing a surface of the substrate to be cleaned. The substrate and structure are brought into contact with a cleaning liquid, which is subsequently subjected to acoustic waves of a given frequency. The nucleation template features easier nucleation formation than the surface that needs to be cleaned by, for example, causing the template to have a higher contact angle when in contact with the liquid than the substrate surface to be clean. Therefore, bubbles nucleate on the structure and not on the surface to be cleaned.
Abstract:
A spot on a layer of a 2D semiconductor material deposited on a substrate is irradiated so as to generate excitons, so that photons are emitted from the layer. The photoluminescence spectrum is recorded for different values of the charge carrier concentration in the layer. The modulation of the charge carrier concentration may be realized by modulating the output power of the light source used to irradiate the sample. The relation is recorded between the ratio of the photoluminescence intensity of a first peak in the spectrum related to radiative recombination from indirect bandgaps to the intensity of a second peak in the spectrum related to radiative recombination from direct bandgaps, and the carrier concentration. This relation is fitted to a model of the ratio that takes into account multiple recombination mechanisms, radiative and non-radiative. From this process, the trap density within the bandgap is derived.
Abstract:
A spot on a layer of a 2D semiconductor material deposited on a substrate is irradiated so as to generate excitons, so that photons are emitted from the layer. The photoluminescence spectrum is recorded for different values of the charge carrier concentration in the layer. The modulation of the charge carrier concentration may be realized by modulating the output power of the light source used to irradiate the sample. The relation is recorded between the ratio of the photoluminescence intensity of a first peak in the spectrum related to radiative recombination from indirect bandgaps to the intensity of a second peak in the spectrum related to radiative recombination from direct bandgaps, and the carrier concentration. This relation is fitted to a model of the ratio that takes into account multiple recombination mechanisms, radiative and non-radiative. From this process, the trap density within the bandgap is derived.
Abstract:
The disclosed technology generally relates to preparing two-dimensional material layers, and more particularly to releasing a graphene layer from a template substrate. According to an aspect, a method of releasing a graphene layer includes providing a template substrate on which the graphene layer is provided, the method comprising: subjecting the graphene layer and the template substrate to a water treatment by soaking the graphene layer and the template substrate in water such that water is intercalated between the template substrate and the graphene layer; and subjecting the graphene layer and the template substrate to a delamination process, thereby releasing the graphene layer from the template substrate.
Abstract:
This present application relates to a system for delivering megasonic energy to a liquid, involving one or more megasonic transducers, each transducer having a single operating frequency within an ultrasound bandwidth and comprising two or more groups of piezoelectric elements arranged in one or more rows, and a megasonic generator means for driving the one or more transducers at frequencies within the bandwidth, the generator means being adapted for changing the voltage applied to each group of piezoelectric elements so as to achieve substantially the same maximum acoustic pressure for each group of piezoelectric elements. The generator means and transducers being constructed and arranged so as to produce ultrasound within the liquid. Such a system may be part of an apparatus for cleaning a surface of an article such as a semiconductor wafer or a medical implant.