NanoTechnology: Materials, Processes & Devices

Research that includes:

  • Development of nanostructure fabrication technology
  • Nanomagnetics, Microphotonics
  • CMOS Integrated Nanowires/Nanotubes (CMOS-Inn)

BPN968: Metal-Organic Framework Based Triboelectric Nanogenerator for Self-Powered Gas Sensing

Jihoon Chung
Adrian K. Davey
Isaac Zakaria
2022

With the rise of interest in the Internet of Things (IoT), the need for low-power sensors for monitoring the working environment has been in spotlight. Considering the number of sensors required to provide real time monitoring, creating sustainable and self-powered sensors is essential. Triboelectric nanogenerator (TENG), which converts mechanical motion to electrical energy, is one of the most promising candidates for realizing self-powered sensors due to its sensitivity to surface material properties and ability to generate consistent signals depending on mechanical input. Here, we...

BPN963: Ordered Porous RGO/SnO2 Thin Films for Ultrasensitive Humidity Detection

Zhou Li
Isaac Zakaria
2022

SnO2-based chemiresistive gas sensors can effectively detect combustible, explosive and toxic gases, and have been widely used in safety monitoring and process control in residential buildings, in various industrial settings and in mines. However, sensitivity and selectivity are still needed to be further improved for most current SnO2-based gas sensors. In addition, their high power consumption due to their high working temperature (200-400°C) limits their further development. Graphene, due to its unique characteristics (such as excellent electrical conductivity, large surface...

Kadircan Godeneli

Graduate Student Researcher
Electrical Engineering and Computer Sciences
Professor Alp Sipahigil (Advisor)
Ph.D. 2026 (Anticipated)
Kadircan received his B.S. degrees in Electrical Engineering and Physics from Bogazici University, Istanbul, Turkey in 2021. He is currently pursuing a Ph.D. in the Quantum Devices Group at UC Berkeley under the supervision of Prof. Alp Sipahigil.

Synthesis and Gas Sensing Properties of NiO/ZnO Heterostructured Nanowires

Sikai Zhao
Yanbai Shen
Yong Xia
Aifei Pan
Zhou Li
Carlo Carraro
Roya Maboudian
2021

In this study, we report on the synthesis of the NiO/ZnO heterostructured nanowires by a facile two-step liquid phase route and their gas sensing characteristics employing Au interdigitated electrodes integrated on a miniature ceramic heater. Microstructural characterizations indicate that flocculent NiO particles are uniformly assembled on the outer surfaces of the single-crystalline ZnO nanowires, with diameters around 50 nm and lengths ranging from 500 nm to several μm. The gas sensing investigation indicates that the sensors based on NiO/ZnO heterostructured nanowires exhibit high...

In-Situ Synthesized N-Doped ZnO for Enhanced CO2 Sensing: Experiments and DFT Calculations

Yong Xia
Aifei Pan
Ya-Qiong Su
Sikai Zhao
Zhou Li
Adrian K. Davey
Libo Zhao
Carlo Carraro
Roya Maboudian
2022

Chemiresistive CO2 sensing is attractive due to low cost and ease of chip-level integration. Our previous studies (Yong Xia, 2021) showed the well-developed ZnO material fabricated by in-situ annealing exhibited good CO2 sensing performance. Here, we have expanded on those studies, including CO2 cyclic tests under both dry air and N2 background whereby a much higher response to CO2 in N2 background was observed. Detailed density functional theory calculations were conducted to understand the behavior. The results indicated nitrogen doping is mainly responsible for the observed response. In...

A New Chemresistive NO2 Sensing Material: Hafnium Diboride

Sikai Zhao
Yong Xia
Steven DelaCruz
Aifei Pan
Zhou Li
Yanbai Shen
Marcus A. Worsley
Carlo Carraro
Roya Maboudian
2022

While metal oxides and metal sulfides have been extensively studied for gas sensing applications, there are no extensive reports on gas sensing properties of metal diborides. Here, for the first time, we have investigated the conductometric gas sensing behavior of HfB2 nanoparticles. The HfB2 nanoparticles is synthesized via a sol-gel method and characterized using X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The gas sensor is fabricated by drop casting the HfB2 nanoparticles on interdigitated Ag/Pd...

BPN704: Vapor-Liquid-Solid Growth of Polycrystalline Indium Phosphide Thin Films on Metal

Wenbo Ji
2021

Here, we develop a technique that enables direct growth of III-V materials on non-epitaxial substrates. Here, by utilizing a planar liquid phase template, we extend the VLS growth mode to enable polycrystalline indium phosphide (InP) thin film growth on Mo foils.

BPN935: Low Temperature Deposited Thin Films for p-Type Field Effect Transistors and Circuits

Chunsong Zhao
2021

Developing low-temperature grown semiconducting films is critical for the development of flexible, transparent and three-dimensional monolithic integrated electronics, however, low processing temperature typically results in a poor crystallinity and a low mobility. Here, we report the realization of low-temperature fabrication of highly crystalline tellurium films with large grain size (average grain area of ~150 um2) by controlling the crystallization process of thermally evaporated Te films. Tellurium single crystals with a lateral dimensional of 6 um are realized on various...

BPN964: Metal Oxide Heterostructure Nanowires for Gas Sensing Applications

Sikai Zhao
2021

Metal oxide semiconducting gas sensors are one of the most widely used gas sensing devices due to their low cost, high reliability, solid-state, and high response. While they have been employed for the detection of various gases and in many applications, several issues remain including their limited selectivity and humidity interference. As the core part of a semiconducting gas sensor, sensing materials play the key role in determining the sensing performance of the device, with the materials’ microstructure and surface properties being the dominant factors. Thus the primary...

Javey Lab: Researchers Demonstrate New Semiconductor Device Possibilities using Black Phosphorus

August 11, 2021
William Schulz

Stress and strain, applied in just the right manner, can sometimes produce amazing results.

That is what researchers, led by a team at UC Berkeley’s Department of Electrical Engineering and Computer Sciences, discovered about an emerging semiconductor material — black phosphorus (BP) — used to make two types of optoelectronic devices: light emitting diodes (LEDs) and photodetectors.

Under mechanical strain, BP can be induced to emit or detect infrared (IR) light in a range of desirable wavelengths — 2.3 to 5.5 micrometers, which spans the short- to mid-wave IR — and to do so...