Calculation of Intrinsic Carrier Density of Ge1−xSnx Alloy, Its Temperature Dependence Around Room Temperature and Its Effect on Maximum Electron Mobility

Author(s):  
Shyamal Mukhopadhyay ◽  
Bratati Mukhopadhyay ◽  
Gopa Sen ◽  
P. K. Basu
2008 ◽  
Vol 600-603 ◽  
pp. 1063-1066 ◽  
Author(s):  
Konstantin Vassilevski ◽  
Keith P. Hilton ◽  
Nicolas G. Wright ◽  
Michael J. Uren ◽  
A.G. Munday ◽  
...  

Trenched and implanted vertical JFETs (TI-VJFETs) with blocking voltages of 700 V were fabricated on commercial 4H-SiC epitaxial wafers. Vertical p+-n junctions were formed by aluminium implantation in sidewalls of strip-like mesa structures. Normally-on 4H-SiC TI-VJFETs had specific on-state resistance (RO-S ) of 8 mW×cm2 measured at room temperature. These devices operated reversibly at a current density of 100 A/cm2 whilst placed on a hot stage at temperature of 500 °C and without any protective atmosphere. The change of RO-S with temperature rising from 20 to 500 °C followed a power law (~ T 2.4) which is close to the temperature dependence of electron mobility in 4H-SiC.


Author(s):  
I. Khidirov ◽  
V. V. Getmanskiy ◽  
A. S. Parpiev ◽  
Sh. A. Makhmudov

This work relates to the field of thermophysical parameters of refractory interstitial alloys. The isochoric heat capacity of cubic titanium carbide TiCx has been calculated within the Debye approximation in the carbon concentration  range x = 0.70–0.97 at room temperature (300 K) and at liquid nitrogen temperature (80 K) through the Debye temperature established on the basis of neutron diffraction analysis data. It has been found out that at room temperature with decrease of carbon concentration the heat capacity significantly increases from 29.40 J/mol·K to 34.20 J/mol·K, and at T = 80 K – from 3.08 J/mol·K to 8.20 J/mol·K. The work analyzes the literature data and gives the results of the evaluation of the high-temperature dependence of the heat capacity СV of the cubic titanium carbide TiC0.97 based on the data of neutron structural analysis. It has been proposed to amend in the Neumann–Kopp formula to describe the high-temperature dependence of the titanium carbide heat capacity. After the amendment, the Neumann–Kopp formula describes the results of well-known experiments on the high-temperature dependence of the heat capacity of the titanium carbide TiCx. The proposed formula takes into account the degree of thermal excitation (a quantized number) that increases in steps with increasing temperature.The results allow us to predict the thermodynamic characteristics of titanium carbide in the temperature range of 300–3000 K and can be useful for materials scientists.


RSC Advances ◽  
2021 ◽  
Vol 11 (41) ◽  
pp. 25731-25737
Author(s):  
Maria Cristina Righetti ◽  
Maria Laura Di Lorenzo ◽  
Patrizia Cinelli ◽  
Massimo Gazzano

At room temperature and at the human body temperature, all the amorphous fraction is mobile in poly(butylene succinate).


2021 ◽  
Vol 10 (1) ◽  
pp. 330-369
Author(s):  
Norizan M. Nurazzi ◽  
Norli Abdullah ◽  
Siti Z. N. Demon ◽  
Norhana A. Halim ◽  
Ahmad F. M. Azmi ◽  
...  

Abstract Graphene is a single-atom-thick sheet of sp2 hybridized carbon atoms that are packed in a hexagonal honeycomb crystalline structure. This promising structure has endowed graphene with advantages in electrical, thermal, and mechanical properties such as room-temperature quantum Hall effect, long-range ballistic transport with around 10 times higher electron mobility than in Si and thermal conductivity in the order of 5,000 W/mK, and high electron mobility at room temperature (250,000 cm2/V s). Another promising characteristic of graphene is large surface area (2,630 m2/g) which has emerged so far with its utilization as novel electronic devices especially for ultrasensitive chemical sensor and reinforcement for the structural component applications. The application of graphene is challenged by concerns of synthesis techniques, and the modifications involved to improve the usability of graphene have attracted extensive attention. Therefore, in this review, the research progress conducted in the previous decades with graphene and its derivatives for chemical detection and the novelty in performance enhancement of the chemical sensor towards the specific gases and their mechanism have been reviewed. The challenges faced by the current graphene-based sensors along with some of the probable solutions and their future improvements are also being included.


2013 ◽  
Vol 1536 ◽  
pp. 119-125 ◽  
Author(s):  
Guillaume Courtois ◽  
Bastien Bruneau ◽  
Igor P. Sobkowicz ◽  
Antoine Salomon ◽  
Pere Roca i Cabarrocas

ABSTRACTWe propose an implementation of the PCD technique to minority carrier effective lifetime assessment in crystalline silicon at 77K. We focus here on (n)-type, FZ, polished wafers passivated by a-Si:H deposited by PECVD at 200°C. The samples were immersed into liquid N2 contained in a beaker placed on a Sinton lifetime tester. Prior to be converted into lifetimes, data were corrected for the height shift induced by the beaker. One issue lied in obtaining the sum of carrier mobilities at 77K. From dark conductance measurements performed on the lifetime tester, we extracted an electron mobility of 1.1x104 cm².V-1.s-1 at 77K, the doping density being independently calculated in order to account for the freezing effect of dopants. This way, we could obtain lifetime curves with respect to the carrier density. Effective lifetimes obtained at 77K proved to be significantly lower than at RT and not to depend upon the doping of the a-Si:H layers. We were also able to experimentally verify the expected rise in the implied Voc, which, on symmetrically passivated wafers, went up from 0.72V at RT to 1.04V at 77K under 1 sun equivalent illumination.


1990 ◽  
Vol 201 ◽  
Author(s):  
Honglie Shen ◽  
Genqing Yang ◽  
Zuyao Zhou ◽  
Guanqun Xia ◽  
Shichang Zou

AbstractDual implantations of Si+ and P+ into InP:Fe were performed both at 200°C and room temperature. Si+ ions were implanted by 150keV with doses ranging from 5×1013 /cm2 to 1×1015 /cm2, while P+ ions were implanted by 110keV. 160keV and 180keV with doses ranging from 1×l013 /cm2 to 1×1015 /cm2. Hall measurements and photoluminescence spectra were used to characterize the silicon nitride encapsulated annealed samples. It was found that enhanced activation can be obtained by Si+ and P+ dual implantations. The optimal condition for dual implantations is that the atomic distribution of implanted P overlaps that of implanted si with the same implant dose. For a dose of 5×l014 /cm2, the highest activation for dual implants is 70% while the activation for single implant is 40% after annealing at 750°C for 15 minutes. PL spectrum measurement was carried out at temperatures from 11K to 100K. A broad band at about 1.26eV was found in Si+ implanted samples, of which the intensity increased with increasing of the Si dose and decreased with increasing of the co-implant P+ dose. The temperature dependence of the broad band showed that it is a complex (Vp-Sip) related band. All these results indicate that silicon is an amphoteric species in InP.


1978 ◽  
Vol 31 (4) ◽  
pp. 791 ◽  
Author(s):  
R Chandramani ◽  
SP Basavaraju ◽  
N Devaraj

Chlorine n.q.r, in 2,6-dichlorophenol has been investigated at temperatures from 77 K to room temperature. Two resonance lines due to chemically inequivalent sites have been observed throughout this temperature range. Torsional frequencies of the molecule have been calculated at temperatures from 77 to 300 K according to Bayer's theory and Brown's method. Also the temperature coefficients of the torsional frequencies have been calculated.


1999 ◽  
Vol 13 (29n31) ◽  
pp. 3758-3763 ◽  
Author(s):  
AUGUST YURGENS ◽  
DAG WINKLER ◽  
TORD CLAESON ◽  
SEONG-JU HWANG ◽  
JIN-HO CHOY

The c-axis tunneling properties of both pristine Bi2212 and its HgBr 2 intercalate have been measured in the temperature range 4.2-250 K. Lithographically patterned 7-10 unit-cell heigh mesa structures on the surfaces of these single crystals were investigated. Clear SIS-like tunneling curves for current applied in the c-axis direction have been observed. The dynamic conductance d I/ d V(V) shows both sharp peaks corresponding to a superconducting gap edge and a dip feature beyond the gap, followed by a wide maximum, which persists up to a room temperature. Shape of the temperature dependence of the c-axis resistance does not change after the intercalation suggesting that a coupling between CuO 2-bilayers has little effect on the pseudogap.


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