Graduate

EST Seminar presents "Oxide Semiconductor Electronics: from BEOL thin film circuits to high-voltage UWBG"

Topic: 
Oxide Semiconductor Electronics: from BEOL thin film circuits to high-voltage UWBG
Abstract / Description: 

Oxide semiconductors' unique properties – a wide bandgap, reasonably high electron mobility, and ease of bulk and thin film preparation – make them prime material candidates for a variety of electronic devices. In this talk, I will describe my group's recent work on amorphous and crystalline oxide semiconductors for back end of line (BEOL) thin film circuitry and for high-voltage ultra-wide bandgap (UWBG) power devices, respectively. First, we exploit the thermodynamics of interfacialin situredox reactions with amorphous zinc tin oxide (a-ZTO) semiconductor to make MISFETs, MESFETs, Schottky diodes, and resistive memory devices that can be monolithically integrated with silicon CMOS. We demonstrate rectifiers that can harvest RFID wireless power and inverters that are compatible with low voltage silicon ICs. Furthermore, we develop novel, scalable atomic layer deposition processes to realize high-qualitya-ZTO semiconductor films, high-kAl2O3gate insulators and passivation layers, and Al:ZnO source/drain electrodes. Combining an innovative electro-hydro-dynamic jetting process with additive and subtractive selective area ALD, we realize thin film transistors with channel lengths below the ink-jet printing limit. I'll also describe our recent work on p-type oxide TFTs using Cu2O, and explain the key challenges in device architecture and materials physics that limit p-TFT performance. Finally, I'll explain how we've taken the learning from thin film oxides and used it to realize ultra-stable ohmic contacts and MOS capacitors to crystalline beta-phase gallium oxide, an ultra-wide bandgap semiconductor of interest for multi-kV power devices.

Date and Time: 
Tuesday, March 30, 2021 - 1:00pm

Mixed Reality for Surgical Guidance

Topic: 
Mixed Reality for Surgical Guidance (featuring the Stanford IMMERS Lab)
Abstract / Description: 

A new virtual panel discussion series about groundbreaking mixed reality technology and innovation in medicine and how it impacts patients, clinicians, and the healthcare industry.

The event will start with a one-hour panel discussion featuring Dr. Bruce Daniel of Stanford Radiology and the Stanford IMMERS Lab; Dr. Thomas Grégory of Orthopedic Surgery at the Université Sorbonne Paris Nord; Christoffer Hamilton of Brainlab, a surgical software and hardware leader in Germany; and Dr. Jennifer Silva of Pediatric Cardiology at Washington University in St. Louis, who founded the medical mixed reality company SentiAR. This panel will be moderated by Dr. Christoph Leuze of Stanford University and the Stanford Medical Mixed Reality (SMMR) program. Immediately following the panel discussion, you are also invited to a 30-minute interactive session with the panelists where questions and ideas can be explored in real time.

 

Stanford Medical Mixed Reality (SMMR) is dedicated to building community across Stanford Medicine together with global industry leaders and academia focusing on medical virtual and augmented reality technology. Founded by the Incubator for Medical Mixed and Extended Reality at Stanford (IMMERS) Lab, we aim to bring together leading researchers, clinicians and engineers to share work, exchange ideas, collaborate and discuss opportunities and challenges. The SMMR Panel Discussion Series highlights labs around Stanford working in this area and focuses on particular topics such as surgical guidance, VR-based therapy, and training & education.

You will receive invitations to upcoming events if you are on the SMMR distribution list. You can add or remove yourself from this list by completing the information here.

Date and Time: 
Thursday, April 1, 2021 - 9:00am

RL Forum Talk: Diffusion Asymptotics for Sequential Experiments

Topic: 
Diffusion Asymptotics for Sequential Experiments
Abstract / Description: 

I will discuss in this talk a new diffusion-asymptotic analysis for sequentially randomized experiments. Rather than taking sample size n to infinity while keeping the problem parameters fixed, we let the mean signal level scale to the order 1/\sqrt{n} so as to preserve the difficulty of the learning task as n gets large. In this regime, we show that the behavior of a class of methods for sequential experimentation converges to a diffusion limit. This connection enables us to make sharp performance predictions and obtain new insights on the behavior of Thompson sampling. Our diffusion asymptotics also help resolve a discrepancy between the Θ(log(n)) regret predicted by the fixed-parameter, large-sample asymptotics on the one hand, and the Θ(\sqrt{n}) regret from worst-case, finite-sample analysis on the other, suggesting that it is an appropriate asymptotic regime for understanding practical large-scale sequential experiments.

Date and Time: 
Tuesday, March 23, 2021 - 1:00pm

Q-FARM presents "Quantum sensing with unlimited optical bandwidth"

Topic: 
Quantum sensing with unlimited optical bandwidth
Abstract / Description: 

Squeezed light is a major resource for quantum sensing, which has been already implemented in high-end interferometric sensing, such as gravitational wave detection. However, standard squeezed interferometry methods suffer from two severe limitations. First, the detection bandwidth of squeezing-enhanced interferometry is limited by the narrowband response (MHz to GHz) of photodetectors, which critically prevents efficient utilization of the optical bandwidth (tens of THz and more) offered by standard sources of squeezed light. Second, current methods require near ideal photo-detectors with unity efficiency, prohibiting real-life applications, where ideal detection is not available. To overcome these limitations and to benefit from the orders-of-magnitude enhancement in the sensing throughput offered by the optical bandwidth, a paradigm shift is required in terms of broadband quantum sources, detection schemes, and interferometric design.

I will present a set of new methods for sub-shot-noise sensing, based on nonlinear interferometry, which overcome these limitations. By placing the phase object in question between two parametric amplifiers in series, the first amplifier generates broadband squeezed light to interrogate the object and the second amplifier acts as an ideal broadband quantum detector to measure the object's response. This technique is robust to detection inefficiency and provides an unprecedentedly broad optical bandwidth for quantum measurement, exceeding the possibilities of photodetectors by several orders of magnitude.

I will discuss in detail two specific examples of ultra broadband parametric-homodyne measurement [1] and of squeezing-enhanced Raman spectroscopy [2].

References:
[1] Y. Shaked, Y. Michael, R. Vered, L. Bello, M. Rosenbluh and A. Pe'er, "Lifting the Bandwidth Limit of Optical Homodyne Measurement", Nature Communications 9, 609 (2018).
[2] Y. Michael, L. Bello, M. Rosenbluh, and A. Pe'er, "Squeezing-enhanced Raman Spectroscopy", npj Quantum Information 5, 81 (2019).

Date and Time: 
Wednesday, March 24, 2021 - 10:00am
Venue: 
Zoom ID: 987 676 025; +password

US-Asia Technology Management Center presents Public Seminar Series on Global Public Health

Topic: 
AI for Healthcare Delivery in Under-served Communities: Challenges and Opportunities
Abstract / Description: 

Presented by: Silicon Valley Global Health and Aaroogya Foundation in cooperation with US-Asia Technology Management Center, Stanford University

 

After registering, you will receive a confirmation email containing information about joining the meeting.

Date and Time: 
Tuesday, March 23, 2021 - 7:00pm
Venue: 
Zoom: register to receive ID

IT-Forum presents "Approximating cross-validation: guarantees for model assessment and selection"

Topic: 
Approximating cross-validation: guarantees for model assessment and selection
Abstract / Description: 

Cross-validation (CV) is the de facto standard for selecting accurate predictive models and assessing model performance. However, CV suffers from a need to repeatedly refit a learning procedure on a large number of training datasets. To reduce the computational burden, a number of works have introduced approximate CV procedures that simultaneously reduce runtime and provide model assessments comparable to CV when the prediction problem is sufficiently smooth. An open question however is whether these procedures are suitable for model selection. In this talk, I'll describe (i) broad conditions under which the model selection performance of approximate CV nearly matches that of CV, (ii) examples of prediction problems where approximate CV selection fails to mimic CV selection, and (iii) an extension of these results and the approximate CV framework more broadly to non-smooth prediction problems like L1-regularized empirical risk minimization.

Date and Time: 
Thursday, March 18, 2021 - 4:30pm
Venue: 
Zoom: register to receive ID

Applied Physics/Physics Colloquium presents "TTbar Deformations, S-matrix, and Density of States"

Topic: 
TTbar Deformations, S-matrix, and Density of States
Abstract / Description: 

Theories in two space-time dimensions provide playground for exploring geometry of the "Theory Space" - the collection of all quantum field theories. Recently introduced "TTbar deformations" of 2D quantum field theories bring insight into the structure of that space. These are special deformations, "irrelevant" in the renormalization group sense and thus likely altering the local structure of the theory. At the same time, the TTbar deformations generate robust and even solvable theories. Of special interest are the deformations of integrable field theories, where they can be related to deformations of the associated factorizable S-matrix, and the theory can be treated using the powerful tool of the Thermodynamic Bethe ansatz. Preliminary results suggest that the deformed theories typically develop Hagedorn-like density of states, similar to that in the string theories.

Date and Time: 
Tuesday, March 16, 2021 - 4:30pm

University Commencement (virtual)

Topic: 
Main commencement
Abstract / Description: 

The main campus-wide celebration will be streamed on the web on Sunday, June 13, at 10 a.m. Pacific time, and there will be additional virtual events and activities during the weekend.

We are committed to doing all that we can to make this a meaningful celebration within the constraints of the pandemic. We are also committed to developing an in-person celebration for our 2021 graduates when conditions allow.


 

 

Date and Time: 
Sunday, June 13, 2021 - 10:00am

Q-FARM presents "Unconventional computing with liquid light"

Topic: 
Unconventional computing with liquid light
Abstract / Description: 

The recent advances in the development of physical platforms for solving combinatorial optimisation problems reveal the future of high-performance computing for quantum and classical devices. Unconventional computing architectures were proposed for numerous systems including superconducting qubits, CMOS hardware, optical parametric oscillators, memristors, lasers, photonic simulators, trapped ions, polariton and photon condensates. A promising approach to achieve computational supremacy over the classical von Neumann architecture explores classical and quantum hardware as Ising and XY machines. Gain-dissipative platforms such as the networks of optical parametric oscillators, coupled lasers and non-equilibrium Bose-Einstein condensates such as exciton-polariton or photon condensates use an approach to finding the global minimum of spin Hamiltonians which is different from quantum annealers or quantum computers. In my talk, I will discuss the principles of the operation of the devices based on such systems with a focus on polariton graph platform that we recently realised in experiments.

Date and Time: 
Wednesday, March 10, 2021 - 12:00pm

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