Ali Javey (Advisor)

Research Advised by Professor Ali Javey

Javey Group:  List of Projects | List of Researchers

Pulsed Electroluminescent Devices for Emission Across Energy and Length Scales

Vivian Wang
Ali Javey

Unusual device architectures may open up unexpected opportunities for optoelectronic devices. For example, the range of luminescent materials that can be easily integrated in light-emitting devices is often limited by material processing and band alignment issues. This hinders the development of electroluminescent devices at extreme wavelengths and the use of electroluminescence spectroscopy as an analytical technique. In this thesis, I explore an unconventional scheme of electrically-driven light emission based on pulsed metal-oxidesemiconductor capacitor devices. This concept can be used...

Naoki Higashitarumizu

Postdoctoral Researcher
Electrical Engineering and Computer Sciences
Professor Ali Javey (Advisor)

Dr. Naoki Higashitarumizu is a postdoctoral fellow in Electrical Engineering and Computer Sciences at UC Berkeley, with a joint appointment as a postdoctoral fellow in the Materials Science Division at Lawrence Berkeley National Laboratory. He received a Ph.D. in material engineering from The University of Tokyo in 2020, and was a postdoctoral fellow at The University of Tokyo in 2020. Dr. Higashitarumizu then joined Javey Research Group in September 2020.

BSAC Spring...

BPN982: Color-Tunable Alternating Current Light Emitting Diodes

Jongchan Kim
Vivian Wang

Alternating current (AC) driven light emitting devices (LEDs) are recently dragging attention due to its efficient color tunability. These devices consist of multilayer structure as the direct current (DC) driven LEDs, but the multilayer structure has drawbacks such as the large amount of material usage that increases the fabrication cost, and the difficult yield control due to a number of processing steps. In contrast, a recently demonstrated AC driven LED with a single contact has several advantages compared to the previous structures such as simple device structure, diverse...

Single-Pixel Reconstructive Mid-Infrared Micro-Spectrometer

Kaichen Dong
Jiachen Li
Tiancheng Zhang
Fangda Gu
Yuhang Cai
Niharika Gupta
Ali Javey
Jie Yao
Junqiao Wu

Miniaturized spectrometers in the mid-infrared (MIR) are critical in developing next-generation portable electronics for advanced sensing and analysis. The bulky gratings or detector/filter arrays in conventional micro-spectrometers set a physical limitation to their miniaturization. In this work, we demonstrate a single-pixel MIR micro-spectrometer that reconstructs the sample transmission spectrum by a spectrally dispersed light source instead of spatially grated light beams. The spectrally tunable MIR light source is realized based on the thermal emissivity engineered via the metal-...

Anomalous Thickness Dependence of Photoluminescence Quantum Yield in Black Phosphorous

Naoki Higashitarumizu
Shiekh Zia Uddin
Daniel Weinberg
Nima Sefidmooye Azar
I K M Reaz Rahman
Vivian Wang
Kenneth B. Crozier
Eran Rabani
Ali Javey

Black phosphorus has emerged as a unique optoelectronic material, exhibiting tunable and high device performance from mid-infrared to visible wavelengths. Understanding the photophysics of this system is of interest to further advance device technologies based on it. Here we report the thickness dependence of the photoluminescence quantum yield at room temperature in black phosphorus while measuring the various radiative and non-radiative recombination rates. As the thickness decreases from bulk to ~4 nm, a drop in the photoluminescence quantum yield is initially observed due to enhanced...

Flexible Vanadium Dioxide Photodetectors for Visible to Longwave Infrared Detection at Room Temperature

Sivacarendran Balendhran
Mohammad Taha
Shifan Wang
Wei Yan
Naoki Higashitarumizu
Dingchen Wen
Nima Sefidmooye Azar
James Bullock
Paul Mulvaney
Ali Javey

Flexible optoelectronics is a rapidly growing field, with a wide range of potential applications. From wearable sensors to bendable solar cells, curved displays, and curved focal plane arrays, the possibilities are endless. The criticality of flexible photodetectors for many of these applications is acknowledged, however, devices that are demonstrated thus far are limited in their spectral range. In this study, flexible photodetectors are demonstrated using a VOx nanoparticle ink, with an extremely broad operating wavelength range of 0.4 to 20 µm. This ink is synthesized using a simple and...

Javey Lab: Berkeley Engineers Develop Multicolored Light-Emitting Array on a Single Chip

May 10, 2023

An array of light-emitting devices with 49 different, individually addressable colors.

An array of light-emitting devices with 49 different, individually addressable colors. (Image by Vivian Wang) With limitless colors, the device may lead to advances in spectroscopy May 10, 2023 by Marni Ellery

Multicolored light-...