2020 New's Items

Searching for New Ferroelectric Materials Using High-Throughput Databases: An Experimental Perspective on BiAlO3 and BiInO3

M. Acharya
S. A. Mack
A. Fernandez
J. Kim
H. Wang
K. Eriguchi
D. Meyers
V. Gopalan
J. B. Neaton
L. W. Martin
2020

Recent advances in high-throughput computational workflows are expanding the realm of materials for a range of applications. Here, we report the experimental evaluation of two such predicted candidate ferroelectric perovskite oxides: BiAlO3 and BiInO3. Attempts were made to synthesize polar BiAlO3 and BiInO3 using pulsed-laser deposition. Despite exploring a wide range of temperatures, pressures, substrates, laser fluences, and so on, attempts to grow BiAlO3...

Tuning of Schottky barrier height using oxygen-inserted (OI) layers and fluorine implantation

Zhang X
Takeuchi H
Connelly D
Hytha M
Mears RJ
Rubin LM
Liu TK
2020

The effects of oxygen-insertion technology and low-energy fluorine (F) implantation on the Schottky barrier height (ΦBp) of a Pt/Ti/p-type Si metal–semiconductor contact are studied via electrical characterizations of Schottky diodes, physical analyses by secondary ion mass spectrometry , and chemical analyses by x-ray photoelectron spectroscopy. It is found that both oxygen-inserted (OI) layers and F can reduce ΦBp due to Ti 2p and Si 2p binding energy shifts before forming gas anneal (FGA) and due to retarded Pt diffusion into Si (facilitating low-ΦBp Pt...

Sublithographic Patterning of Spin-Coated SiARC Films Using Tilted Ion Implantation

Rembert TR
Sharma S
Garcia L
Connelly D
Tomoya T
Sakai T
Liu TK
2020

Tilted ion implantation (TII) used in conjunction with preexisting masking features on the surface of a wafer is a relatively low-cost method for sublithographic patterning. Previous demonstrations of this method utilized a thin thermally grown layer of silicon oxide (SiO2) as the implanted layer, with amorphous-silicon masking features, to form patterns with feature sizes as small as 9 nm. In this article, this method is adapted to be compatible with back-end-of-line (BEOL) processing using silicon-containing antireflection coating (SiARC) as the implanted layer, with photoresist masking...

Evaporated SexTe1-x Thin Films with Tunable Bandgaps for Short-Wave Infrared Photodetectors

Tan C
Amani M
Zhao C
Hettick M
Song X
Lien DH
Li H
Yeh M
Shrestha VR
Crozier KB
Scott MC
2020

Semiconducting absorbers in high-performance short-wave infrared (SWIR) photodetectors and imaging sensor arrays are dominated by single-crystalline germanium and III-V semiconductors. However, these materials require complex growth and device fabrication procedures. In this work, thermally evaporated Sex Te1-x alloy thin films with tunable bandgaps for the fabrication of high-performance SWIR photodetectors are reported. From absorption measurements, it is shown that the bandgaps of Sex Te...

Nicotine Monitoring with a Wearable Sweat Band

Tai LC
Ahn CH
Nyein HY
Ji W
Bariya M
Lin Y
Li L
Javey A
2020

The tobacco epidemic is a public health threat that has taken a heavy toll of lives around the globe each year. Smoking affects both the smokers and those who are exposed to secondhand smoke, and careful tracking of exposure can be key to mitigating the potential hazards. For smokers, the variation of chemical compositions between commercial cigarettes has led to ambiguity in estimating the health risks, both for active smokers and others involuntarily exposed to tobacco smoke and byproducts. In this regard, sweat possesses an attractive opportunity to monitor smoke exposure due to...

Polymeric Electron-Selective Contact for Crystalline Silicon Solar Cells with an Efficiency Exceeding 19%

Ji W
Allen T
Yang X
Zeng G
De Wolf S
Javey A
2020

Carrier-selective contacts have become a prominent path forward toward efficient crystalline silicon (c-Si) photovoltaics. Among the proposed contacting materials, organic materials may offer simplified and low-cost processing compared with typical vacuum deposition techniques. Here, branched polyethylenimine (b-PEI) is presented as an electrontransport layer (ETL) for c-Si solar cells. The incorporation of a b-PEI interlayer between c-Si(n) and Al leads to a low contact resistivity of 24 mΩ cm2 . A silicon heterojunction solar cell integrated with b-PEI is demonstrated achieving a power...