Field distribution and collection efficiency in an AlGaN metal–semiconductor–metal detector

2002 ◽  
Vol 91 (9) ◽  
pp. 6095-6098 ◽  
Author(s):  
L. Hirsch ◽  
P. Moretto ◽  
J. Y. Duboz ◽  
J. L. Reverchon ◽  
B. Damilano ◽  
...  
Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 795
Author(s):  
Soumava Ghosh ◽  
Kuan-Chih Lin ◽  
Cheng-Hsun Tsai ◽  
Harshvardhan Kumar ◽  
Qimiao Chen ◽  
...  

Metal-semiconductor-metal photodetectors (MSM PDs) are effective for monolithic integration with other optical components of the photonic circuits because of the planar fabrication technique. In this article, we present the design, growth, and characterization of GeSn MSM PDs that are suitable for photonic integrated circuits. The introduction of 4% Sn in the GeSn active region also reduces the direct bandgap and shows a redshift in the optical responsivity spectra, which can extend up to 1800 nm wavelength, which means it can cover the entire telecommunication bands. The spectral responsivity increases with an increase in bias voltage caused by the high electric field, which enhances the carrier generation rate and the carrier collection efficiency. Therefore, the GeSn MSM PDs can be a suitable device for a wide range of short-wave infrared (SWIR) applications.


2014 ◽  
Vol 25 (5) ◽  
pp. 055501 ◽  
Author(s):  
Qiang Xu ◽  
Qijin Cheng ◽  
Jinxiang Zhong ◽  
Weiwei Cai ◽  
Zifeng Zhang ◽  
...  

Author(s):  
T. Yanaka ◽  
K. Shirota

It is significant to note field aberrations (chromatic field aberration, coma, astigmatism and blurring due to curvature of field, defined by Glaser's aberration theory relative to the Blenden Freien System) of the objective lens in connection with the following three points of view; field aberrations increase as the resolution of the axial point improves by increasing the lens excitation (k2) and decreasing the half width value (d) of the axial lens field distribution; when one or all of the imaging lenses have axial imperfections such as beam deflection in image space by the asymmetrical magnetic leakage flux, the apparent axial point has field aberrations which prevent the theoretical resolution limit from being obtained.


Author(s):  
H. Rose

The scanning transmission electron microscope offers the possibility of utilizing inelastically scattered electrons. Use of these electrons in addition to the elastically scattered electrons should reduce the scanning time (dose) Which is necessary to keep the quantum noise below a certain level. Hence it should lower the radiation damage. For high resolution, Where the collection efficiency of elastically scattered electrons is small, the use of Inelastically scattered electrons should become more and more favorable because they can all be detected by means of a spectrometer. Unfortunately, the Inelastic scattering Is a non-localized interaction due to the electron-electron correlation, occurring predominantly at the circumference of the atomic electron cloud.


Author(s):  
P.E. Batson

Use of the STEM to obtain precise electronic information has been hampered by the lack of energy loss analysis capable of a resolution and accuracy comparable to the 0.3eV energy width of the Field Emission Source. Recent work by Park, et. al. and earlier by Crewe, et. al. have promised magnetic sector devices that are capable of about 0.75eV resolution at collection angles (about 15mR) which are great enough to allow efficient use of the STEM probe current. These devices are also capable of 0.3eV resolution at smaller collection angles (4-5mR). The problem that arises, however, lies in the fact that, even with the collection efficiency approaching 1.0, several minutes of collection time are necessary for a good definition of a typical core loss or electronic transition. This is a result of the relatively small total beam current (1-10nA) that is available in the dedicated STEM. During this acquisition time, the STEM acceleration voltage may fluctuate by as much as 0.5-1.0V.


Author(s):  
M. Strojnik

Magnetic lenses operating in partial saturation offer two advantages in HVEM: they exhibit small cs and cc and their power depends little on the excitation IN. Curve H, Fig. 1, shows that the maximal axial flux density Bz max of one of the lenses investigated changes between points (3) and (4) by 5% as the excitation varies by 40%. Consequently, the designer can relax the requirements concerning the stability of the lens current supplies. Saturated lenses, however, can only be used if (i) unwanted fields along the optical axis can be controlled, (ii) 'wobbling' of the optical axis due to inhomogeneous saturation around the pole piece faces is prevented, (iii) ample ampere-turns can be squeezed into the space available, and (iv) the lens operating point covers a sufficient range of accelerating voltages.


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