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Full-Text Articles in Engineering Science and Materials

Influence Of Flow Rate, Nozzle Speed, Pitch And The Number Of Passes On The Thickness Of S1805 Photoresist In Suss Microtec As8 Spray Coater, Rohan Sanghvi, Gyuseok Kim Oct 2019

Influence Of Flow Rate, Nozzle Speed, Pitch And The Number Of Passes On The Thickness Of S1805 Photoresist In Suss Microtec As8 Spray Coater, Rohan Sanghvi, Gyuseok Kim

Tool Data

S1805 positive photoresist has been deposited on single crystalline Si wafers using a Suss MicroTec Alta Spray. The influence of flow rate, nozzle speed, pitch and number of passes on the thickness of the photoresist was studied. Results show that the thickness of S1805 is linearly proportional to the flow rate and number of passes, and inversely proportional to the nozzle speed and pitch.


Flexible, Photopatterned, Colloidal Cdse Semiconductor Nanocrystal Integrated Circuits, Franklin Scott Stinner Jan 2017

Flexible, Photopatterned, Colloidal Cdse Semiconductor Nanocrystal Integrated Circuits, Franklin Scott Stinner

Publicly Accessible Penn Dissertations

As semiconductor manufacturing pushes towards smaller and faster transistors, a parallel goal exists to create transistors which are not nearly as small. These transistors are not intended to match the performance of traditional crystalline semiconductors; they are designed to be significantly lower in cost and manufactured using methods that can make them physically flexible for applications where form is more important than speed. One of the developing technologies for this application is semiconductor nanocrystals.

We first explore methods to develop CdSe nanocrystal semiconducting “inks” into large-scale, high-speed integrated circuits. We demonstrate photopatterned transistors with mobilities of 10 cm2/Vs on ...


Microwave Impedance Microscopy Of Nanostructured Carbon, Timothy Scott Jones Jan 2016

Microwave Impedance Microscopy Of Nanostructured Carbon, Timothy Scott Jones

Publicly Accessible Penn Dissertations

Microwave impedance microscopy (MIM) is a scanning probe technique that measures local changes in tip-sample admittance. The imaginary part of the reported change is calibrated with finite element simulations and physical measurements of a standard capacitive sample, and thereafter the output ∆Y is given a reference value in siemens. Simulations also provide a means of extracting sample conductivity and permittivity from admittance, a procedure verified by comparing the estimated permittivity of polytetrafluoroethlyene (PTFE) to the accepted value. Finally, the well-known effective medium approximation of Bruggeman is considered as a means of estimating the volume fractions of the constituents in inhomogeneous ...


Crystal-Amorphous Transformation Via Defect-Templating In Phase-Change Materials, Pavan Nukala Jan 2015

Crystal-Amorphous Transformation Via Defect-Templating In Phase-Change Materials, Pavan Nukala

Publicly Accessible Penn Dissertations

Phase-change materials (PCM) such as GeTe and Ge-Sb-Te alloys are potential candidates for non-volatile memory applications, because they can reversibly and rapidly transform between a crystalline phase and an amorphous phase with medium-range order. Traditionally, crystal-amorphous transformation in these materials has been carried out via melt-quench pathway, where the crystalline phase is heated beyond its melting point by the rising edge of an electric pulse, and the melt phase is quenched by the falling edge into a glassy phase. Formation of an intermediate melt phase in this transformation pathway requires usage of large switching current densities, resulting in energy wastage ...


Flexible Electronics Based On Solution Processable Organic Semiconductors And Colloidal Semiconductor Nanocrystals, Yuming Lai Jan 2014

Flexible Electronics Based On Solution Processable Organic Semiconductors And Colloidal Semiconductor Nanocrystals, Yuming Lai

Publicly Accessible Penn Dissertations

Solution-processable semiconductors hold great potential for the large-area, low-cost fabrication of flexible electronics. Recent advances in flexible electronics have introduced new functional devices such as light-weight displays and conformal sensors. However, key challenges remain to develop flexible devices from emerging materials that use simple fabrication processes and have high-performance.

In this thesis, we first use a solution-processable organic semiconductor to build field-effect transistors on large-area plastic with mobility of 0.1 cm^2/Vs. Combined with passive components, we are able to build voltage amplifiers to capture few mV amplitude bio-signals. This work provides a proof of concept on applying ...


Resistance Switching Devices Based On Amorphous Insulator-Metal Thin Films, Xiang Yang Jan 2014

Resistance Switching Devices Based On Amorphous Insulator-Metal Thin Films, Xiang Yang

Publicly Accessible Penn Dissertations

Nanometallic resistance switching devices based on amorphous insulator-metal thin films are developed to provide a novel non-volatile resistance-switching random-access memory (RRAM) that is CMOS-compatible and meeting technological demand. In these devices, data recording/converting is controlled by a bipolar voltage, which tunes electron localization lengths, hence resistivity, through electron trapping and detrapping. The low-resistance state is a metallic state while the high-resistance state is an insulating state, as established by conductivity studies from 2K to 300K.

The material is exemplified by a Si3N4 thin film with randomly dispersed Pt or Cr. It has been extended to other ...


Designing Nanomaterials For Electronic And Optoelectronic Devices Through Charge Carrier Control, Soong Ju Oh Jan 2014

Designing Nanomaterials For Electronic And Optoelectronic Devices Through Charge Carrier Control, Soong Ju Oh

Publicly Accessible Penn Dissertations

Colloidal semiconductor nanocrystals (NCs) have been shown to be promising materials for electronic and optoelectronic device applications because of their unique size-dependent properties and low-cost solution processability. However, the integration of these materials into devices has been challenging due to a lack of available methods to: 1) accurately control charge carrier statistics, such as majority carrier type and concentration, and carrier mobilities, and 2) efficiently passivate surface defects inherent in NC materials arising from their high surface-volume ratio.

In this thesis, we study the fundamental physics of charge carriers paramount for device application. Then, we introduce several measurement techniques to ...


Interface Engineering To Control Charge Transport In Colloidal Semiconductor Nanowires And Nanocrystals, David Kiewook Kim Jan 2012

Interface Engineering To Control Charge Transport In Colloidal Semiconductor Nanowires And Nanocrystals, David Kiewook Kim

Publicly Accessible Penn Dissertations

Colloidal semiconductor nanocrystals (NCs) are a class of materials that has rapidly gained prominence and has shown the potential for large area electronics. These materials can be synthesized cheaply and easily made in high quality, with tunable electronic properties. However, evaluating if colloidal nanostructures can be used as a viable semiconducting material for large area electronics and more complex integrated circuits has been a long standing question in the field. When these materials are integrated into solid-state electronics, multiple interfaces need to be carefully considered to control charge transport, these interfaces are the: metal contact/semiconductor, dielectric/semiconductor and the ...