Ali Javey (Advisor)

Research Advised by Professor Ali Javey

Javey Group:  List of Projects | List of Researchers

BPN462: Programmable Matter

Xiaobo Zhang
Bryan Schubert
2011

Poly NIPAM (N-isopropylacrylamide) is a kind of thermal responsive polymer that can be synthesized by polymerize NIPAM monomer from its water solution by UV radiation or other synthetic methods. The main impetus to study this material is due to its novel thermal behaviors such as "squeezing out" water from inside, switching from hydrophilic to hydrophobic and changing from transparent to opaque when heating up to its phase transition temperature. Numerous poly NIPAM co- polymers and composites were made to utilize these properties for drug delivery, chemical connectors, and optical...

BPN531: Gigahertz Operation of Flexible Transistors Using InAs Nanomaterial Arrays

Toshitake Takahashi
Kuniharu Takei
2011

In this project, we present NW-based high frequency flexible transistors operating in gigahertz regime. InAs NWs are printed on polyimide (PI) substrate with contact printing method, in which semiconducting NWs on the growth chip can be directly transferred to and aligned on the receiver substrate. Thus fabricated NW-based devices have ft = 1.04 GHz (unit transit frequency of the current gain) and fmax = 1.8 GHz (maximum frequency of oscillation). These results promise the potential of NW-based flexible TFT for future microwave applications.

Project end date: 08/...

BPN583: Development of Functional Nanowire Devices

Min Hyung Lee
2011

Semiconductor nanowires have been widely studied for applications such as sensors, photovoltaics, field-effect transistors, and lasers due to their unique physical properties. However, controlling the density and alignment of nanowires over large-area is still challenging for commercial applications. In this project, we plan to design programmable nanowire integration and actuation methods using soft matters. Field-effect transistors and sensing devices will be tested.

Project end date: 08/17/11

BPN581: Shape-Controlled Synthesis of Single-Crystalline Nanopillar Arrays by Template-Assisted Vapor-Liquid-Solid Process

Onur Ergen
Daniel J. Ruebusch
Hui Fang
2011

In this work highly regular, single-crystalline nanopillar arrays with tunable shapes and geometry are synthesized by the template-assisted vapor-liquid-solid growth mechanism. The grown nanopillars faithfully reproduce the shape of the pores because during the growth the liquid catalyst seeds fill the space available, thereby conforming to the pore geometry. The process is highly generic for various material systems, and as an example, CdS and Ge nanopillar arrays with square, rectangular, and circular cross- sections are demonstrated. This technique has great potential im many...

BPN577: Ultra-Thin Body, Mixed Anion Arsenide-Antimonide XOI FETs

Hui Fang
Steven Chuang
Kuniharu Takei
Ali Javey
2011

We demonstrate ultrathin body (UTB) high mobility InAsSb-on-insulator (XOI) n-FETs. The devices are obtained by the epitaxial layer transfer (ELT) of ultrathin InAsSb layers (thickness, 7-17 nm) onto Si/SiO2 substrates. InAsSb XOI FETs exhibit a peak effective mobility of ~5000 cm2/V-s and an ION/IOFF ratio of over 104. The top-gated devices exhibit an impressive ION of ~0.24 mA/μm (LG~500 nm) at VDD=0.5 V and a SS of ~109 mV/dec. These results demonstrate the utility of the XOI platform for obtaining high mobility n-FETs on Si by using mixed anion arsenide-antimonide as the active...

BPN528: Graphene Synthesis

Maxwell Zheng
Kuniharu Takei
Steven Chuang
2011

This project focuses on various methods of synthesizing device quality graphene for simple integration into semiconductor process flows.

Project end date: 08/18/11

BPN461: Low Energy Electronics

Ha sul Kim
2011

We introduce a novel transistor based on the inter-band tunneling by III-V materials. The type II staggered heterojunction between two compound semiconductors can provide an electron tunneling by quantum mechanical effect from the valence band to the conduction band of semiconductors, and result in reduced sub-threshold swing compared to diffusion in MOSFETs. This allows for these devices to be operated at lower voltages, and thus function with less power consumption.

Project end date: 08/18/11

BPN579: Top-Down and Bottom-Up Approaches to Anti-Reflective Templates for Efficient Photoelectrochemical Solar-to-Fuel Conversion

Cary Pint
2011

Due to tightened regulations on environmental control and high demand on clean fuel, there is great interest in developing a method whose process and product are both eco-friendly. Hydrogen is a fuel of high quality and zero emission. Hydrogen can be directly produced by splitting water into H2 and O2. This project focuses on photochemical splitting of water using solar energy and InP as the photocatalyst. In an effort to enhance the efficiency, the InP is textured to have very low reflectivity.

Project end date: 08/19/11

BPN465: Conformal Ultra-shallow Junction Formation for 3-D Structured InP Nanopillar Solar Cell

Kee Cho
Onur Ergen
Rehan Kapadia
2011

Solar energy represents one of the most abundant and yet least harvested source of renewable energy. We report a PV structure that incorporates 3D, single crystalline n-CdS nanopillars, embedded in poly- crystalline thin films of p-CdTe, to enable high absorption of light and efficient collection of the carriers. Through experiments and modeling, we demonstrate the potency of this approach for enabling highly versatile solar modules on both rigid and flexible substrates with enhanced carrier collection efficiency arising from the geometric configuration of the NPLs. We performed...

BPN647: Ultra-Thin Body, Mixed Anion Arsenide-Antimonide XOI FETs

Hui Fang
Steven Chuang
Kuniharu Takei
2011

We demonstrate ultrathin body (UTB) high mobility InAsSb-on-insulator (XOI) n-FETs. The devices are obtained by the epitaxial layer transfer (ELT) of ultrathin InAsSb layers (thickness, 7-17 nm) onto Si/SiO2 substrates. InAsSb XOI FETs exhibit a peak effective mobility of ~5000 cm2/V-s and an ION/IOFF ratio of over 104. The top-gated devices exhibit an impressive ION of ~0.24 mA/micron (LG~500 nm) at VDD=0.5 V and a SS of ~109 mV/dec. These results demonstrate the utility of the XOI platform for obtaining high mobility n-FETs on Si by using mixed anion arsenide-antimonide as the...