scholarly journals An Integrated Germanium-Based THz Impulse Radiator with an Optical Waveguide Coupled Photoconductive Switch in Silicon

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 367 ◽  
Author(s):  
Peiyu Chen ◽  
Mostafa Hosseini ◽  
Aydin Babakhani

This paper presents an integrated germanium (Ge)-based THz impulse radiator with an optical waveguide coupled photoconductive switch in a low-cost silicon-on-insulator (SOI) process. This process provides a Ge thin film, which is used as photoconductive material. To generate short THz impulses, N++ implant is added to the Ge thin film to reduce its photo-carrier lifetime to sub-picosecond for faster transient response. A bow-tie antenna is designed and connected to the photoconductive switch for radiation. To improve radiation efficiency, a silicon lens is attached to the substrate-side of the chip. This design features an optical-waveguide-enabled “horizontal” coupling mechanism between the optical excitation signal and the photoconductive switch. The THz emitter prototype works with 1550 nm femtosecond lasers. The radiated THz impulses achieve a full-width at half maximum (FWHM) of 1.14 ps and a bandwidth of 1.5 THz. The average radiated power is 0.337 μ W. Compared with conventional THz photoconductive antennas (PCAs), this design exhibits several advantages: First, it uses silicon-based technology, which reduces the fabrication cost; second, the excitation wavelength is 1550 nm, at which various low-cost laser sources operate; and third, in this design, the monolithic excitation mechanism between the excitation laser and the photoconductive switch enables on-chip programmable control of excitation signals for THz beam-steering.

Author(s):  
T. P. Nolan

Thin film magnetic media are being used as low cost, high density forms of information storage. The development of this technology requires the study, at the sub-micron level, of morphological, crystallographic, and magnetic properties, throughout the depth of the deposited films. As the microstructure becomes increasingly fine, widi grain sizes approaching 100Å, the unique characterization capabilities of transmission electron microscopy (TEM) have become indispensable to the analysis of such thin film magnetic media.Films were deposited at 225°C, on two NiP plated Al substrates, one polished, and one circumferentially textured with a mean roughness of 55Å. Three layers, a 750Å chromium underlayer, a 600Å layer of magnetic alloy of composition Co84Cr14Ta2, and a 300Å amorphous carbon overcoat were then sputter deposited using a dc magnetron system at a power of 1kW, in a chamber evacuated below 10-6 torr and filled to 12μm Ar pressure. The textured medium is presently used in industry owing to its high coercivity, Hc, and relatively low noise. One important feature is that the coercivity in the circumferential read/write direction is significandy higher than that in the radial direction.


2020 ◽  
Vol 140 (12) ◽  
pp. 369-373
Author(s):  
Hiroyuki Nikkuni ◽  
Chizuru Numata ◽  
Ryoto Yamaji ◽  
Hiroshi Ito ◽  
Yoshio Kawamata

JETP Letters ◽  
2020 ◽  
Vol 112 (3) ◽  
pp. 145-149
Author(s):  
S. N. Nikolaev ◽  
M. A. Chernopitsskii ◽  
V. S. Bagaev ◽  
V. S. Krivobok

1998 ◽  
Vol 72 (10) ◽  
pp. 1199-1201 ◽  
Author(s):  
Hank Shin ◽  
Stella Hong ◽  
Tom Wetteroth ◽  
Syd R. Wilson ◽  
Dieter K. Schroder

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1099
Author(s):  
Ye-Ji Han ◽  
Se Hyeong Lee ◽  
So-Young Bak ◽  
Tae-Hee Han ◽  
Sangwoo Kim ◽  
...  

Conventional sol-gel solutions have received significant attention in thin-film transistor (TFT) manufacturing because of their advantages such as simple processing, large-scale applicability, and low cost. However, conventional sol-gel processed zinc tin oxide (ZTO) TFTs have a thermal limitation in that they require high annealing temperatures of more than 500 °C, which are incompatible with most flexible plastic substrates. In this study, to overcome the thermal limitation of conventional sol-gel processed ZTO TFTs, we demonstrated a ZTO TFT that was fabricated at low annealing temperatures of 350 °C using self-combustion. The optimized device exhibited satisfactory performance, with μsat of 4.72 cm2/V∙s, Vth of −1.28 V, SS of 0.86 V/decade, and ION/OFF of 1.70 × 106 at a low annealing temperature of 350 °C for one hour. To compare a conventional sol-gel processed ZTO TFT with the optimized device, thermogravimetric and differential thermal analyses (TG-DTA) and X-ray photoelectron spectroscopy (XPS) were implemented.


2018 ◽  
Vol 221 ◽  
pp. 216-219 ◽  
Author(s):  
Y. Yusoff ◽  
P. Chelvanathan ◽  
N. Kamaruddin ◽  
Md. Akhtaruzzaman ◽  
N. Amin

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