The blue-shift effect of the ion-milling-formed HgCdTe photodiodes

Author(s):  
F. X. Zha ◽  
J. Shao
2019 ◽  
Vol 1221 ◽  
pp. 012014
Author(s):  
J A Medina Vázquez ◽  
E Y González Ramírez ◽  
J G Murillo-Ramírez ◽  
V M Carrillo-Vázquez ◽  
G Herrera ◽  
...  

2007 ◽  
Vol 90 (20) ◽  
pp. 201112 ◽  
Author(s):  
F. X. Zha ◽  
Jun Shao ◽  
J. Jiang ◽  
W. Y. Yang

2008 ◽  
Vol 8 (6) ◽  
pp. 2955-2963 ◽  
Author(s):  
S. Tripathi ◽  
R. Brajpuriya ◽  
A. Sharma ◽  
A. Soni ◽  
G. S. Okram ◽  
...  

In the present paper, we have investigated structural, optical as well as electronic properties of electron beam evaporated Ge thin films having layer thicknesses ranging from ultra-thin (5 nm) to thick (200 nm). The Raman spectra show that all peaks are shifted towards lower wave number as compared to their bulk counterparts and are considered as a signature of nanostructure formation and quantum confinement effect. The Raman line exhibits transformation from nanocrystalline to microcrystalline phase with a reduction in blue shift of peak position with increase in Ge film thickness (>5 nm). Similarly, the optical absorption spectra corresponding to these films also show reduction in blue shift effect, although Ge 5 nm film shows the absorption behaviour quite different from higher thickness films. The corresponding band gap values obtained from absorption measurements are much larger than bulk Ge and are mainly attributed to the effect of quantum confinement as expected for small size particles calculated from GIXRD patterns. AFM data in each case are correlated and discussed with structural as well as optical results to support the effect of growth morphology on the above-mentioned observations. The results are further supported by photoelectron spectroscopy (PES), photoluminescence (PL) and resistivity measurements and are interpreted in terms of crystallinity and quantum confinement effect.


2015 ◽  
Vol 9 (1) ◽  
pp. 113-118
Author(s):  
Xinding Yao ◽  
Ruina Fang ◽  
Hongjian Pang ◽  
Guoji Liu

In this paper, 2,3,3-trimethyl-3H-indolin was synthesized by phenylhydrazine and 3-methyl-2-butanone as raw materials in the acetic acid reacted with different nitrogenalkylating reagents. Semi mono-cyanine dye and semi dicyanine dye were prepared with the help of squaric acid diethyl ester. The spectral properties of the target products were checked. The results show that compared with symmetrical squarylium mono-indocyanine dyes with the same substituent, the photo-stability of the bi-cyanine dyes were much better. When dissolved in water, the dye showed shorter maximum absorption wavelength, shorter maximum emission wavelength and shorter Stokes shift and apparent aggregation. In protic solvents, dye spectra showed a blue shift effect with an increase of solution polarity, while in aprotic solvents, dye spectrum showed a red shift with solution polarity increased. Among different solvents, the photostability of the dye in methanol is strongest.


Author(s):  
L. D. Ackerman ◽  
S. H. Y. Wei

Mature human dental enamel has presented investigators with several difficulties in ultramicrotomy of specimens for electron microscopy due to its high degree of mineralization. This study explores the possibility of combining ion-milling and high voltage electron microscopy as a means of circumventing the problems of ultramicrotomy.A longitudinal section of an extracted human third molar was ground to a thickness of about 30 um and polarized light micrographs were taken. The specimen was attached to a single hole grid and thinned by argon-ion bombardment at 15° incidence while rotating at 15 rpm. The beam current in each of two guns was 50 μA with an accelerating voltage of 4 kV. A 20 nm carbon coating was evaporated onto the specimen to prevent an electron charge from building up during electron microscopy.


Author(s):  
G. G. Shaw

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.


Author(s):  
E.J. Jenkins ◽  
D.S. Tucker ◽  
J.J. Hren

The size range of mineral and ceramic particles of one to a few microns is awkward to prepare for examination by TEM. Electrons can be transmitted through smaller particles directly and larger particles can be thinned by crushing and dispersion onto a substrate or by embedding in a film followed by ion milling. Attempts at dispersion onto a thin film substrate often result in particle aggregation by van der Waals attraction. In the present work we studied 1-10 μm diameter Al2O3 spheres which were transformed from the amprphous state to the stable α phase.After the appropriate heat treatment, the spherical powders were embedded in as high a density as practicable in a hard EPON, and then microtomed into thin sections. There are several advantages to this method. Obviously, this is a rapid and convenient means to study the microstructure of serial slices. EDS, ELS, and diffraction studies are also considerably more informative. Furthermore, confidence in sampling reliability is considerably enhanced. The major negative feature is some distortion of the microstructure inherent to the microtoming operation; however, this appears to have been surprisingly small. The details of the method and some typical results follow.


Author(s):  
R.R. Russell

Transmission electron microscopy of metallic/intermetallic composite materials is most challenging since the microscopist typically has great difficulty preparing specimens with uniform electron thin areas in adjacent phases. The application of ion milling for thinning foils from such materials has been quite effective. Although composite specimens prepared by ion milling have yielded much microstructural information, this technique has some inherent drawbacks such as the possible generation of ion damage near sample surfaces.


Author(s):  
P.G. Pawar ◽  
P. Duhamel ◽  
G.W. Monk

A beam of ions of mass greater than a few atomic mass units and with sufficient energy can remove atoms from the surface of a solid material at a useful rate. A system used to achieve this purpose under controlled atmospheres is called an ion miliing machine. An ion milling apparatus presently available as IMMI-III with a IMMIAC was used in this investigation. Unless otherwise stated, all the micro milling operations were done with Ar+ at 6kv using a beam current of 100 μA for each of the two guns, with a specimen tilt of 15° from the horizontal plane.It is fairly well established that ion bombardment of the surface of homogeneous materials can produce surface topography which resembles geological erosional features.


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