Temperature-dependent Raman investigation on suspended graphene: Contribution from thermal expansion coefficient mismatch between graphene and substrate

Carbon ◽  
2016 ◽  
Vol 104 ◽  
pp. 27-32 ◽  
Author(s):  
Shibing Tian ◽  
Yang Yang ◽  
Zhe Liu ◽  
Chao Wang ◽  
Ruhao Pan ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Temperature Dependent ◽  
Suspended Graphene ◽  
Thermal Expansion Coefficient Mismatch

Size- and temperature-dependent Young's modulus and size-dependent thermal expansion coefficient of thin films

2016 ◽  
Vol 18 (31) ◽  
pp. 21508-21517 ◽  
Author(s):  
Xiao-Ye Zhou ◽  
Bao-Ling Huang ◽  
Tong-Yi Zhang
Keyword(s):  
Thin Films ◽  
Thermal Expansion ◽  
Young’S Modulus ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Material Properties ◽  
Essential Role ◽  
Young's Modulus ◽  
Temperature Dependent ◽  
Size Dependent

Surfaces of nanomaterials play an essential role in size-dependent material properties.

scholarly journals Volumetric Properties in the NaAsO2 + H2O System at Temperature from 283.15 to 363.15 K and Atmospheric Pressure

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Hongfang Hou ◽  
Wanjing Cui ◽  
Jiaojiao Chen ◽  
Lingzong Meng ◽  
Yafei Guo ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Molar Volume ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Apparent Molar Volume ◽  
Correlation Coefficients ◽  
Apparent Molar Volumes ◽  
Temperature Dependent ◽  
Molar Volumes ◽  
Experimental Values

Densities of sodium arsenite (NaAsO2) aqueous solution with the molality varied from 0.19570 to 1.94236 mol·kg−1 at temperature intervals of 5 K from 283.15 to 363.15 K and 101 ± 5 kPa were measured by a precise Anton Paar Digital vibrating-tube densimeter. Apparent molar volumes (VΦ) and thermal expansion coefficient (α) were obtained on the basis of experimental data. The 3D diagram of apparent molar volume against temperature and molality and the diagram of thermal expansion coefficient against molality were generated. According to the Pitzer ion-interaction equation of the apparent molar volume model, the Pitzer single-salt parameters (βM,X0υ, βM,X1υ, βM,X2υ, and CM,Xυ, MX = NaAsO2) and their temperature-dependent correlation F(i, p, T) = a1 + a2ln (T/298.15) + a3(T − 298.15) + a4/(620 − T) + a5/(T − 227) (where T is temperature in Kelvin and ai are the correlation coefficients) for NaAsO2 were obtained for the first time. The predictive apparent molar volumes agree well with the experimental values, and those results indicated that the single-salt parameters and the temperature-dependent formula are reliable.

Thermal Effects Analysis of Flip Chip LED Packages with through Silicon via (TSV) by Using Numerical Simulation

2013 ◽  
Vol 459 ◽  
pp. 289-294
Author(s):  
Chi Hui Chien ◽  
Bo Syun Chen ◽  
Yii Der Wu
Keyword(s):  
Thermal Expansion ◽  
Integrated Circuits ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Flip Chip ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Optical Efficiency ◽  
Through Silicon Via ◽  
Thermal Expansion Coefficient Mismatch

With advancement of technology, package sizes and products are becoming smaller due to miniaturization. Separate light-emitting diode (LED) chips and control integrated circuits with through silicon via (TSV) structurescan be combined to achieve reduced size. LED chipswithFlip Chip structureare capable of higher optical efficiency and heat dissipation. Analysis of LED chip structure after heat-related destruction of the chip indicated that the chip suffered stress from heating and cooling. The material used for TSV structures is copper, sincethis provides good electrical conductivity and high thermal conductivity. However, the thermal expansion coefficient of copper is higher than for other materials and can result in thermal expansion coefficient mismatch. Hence, the use of this material is likely to cause stress concentration and thus cause damage. In this study, molybdenum and tungsten were tested as replacements for copper in TSV, and the modified TSV was subjected to simulation analysis.The results indicate that replacement of TSV materials can reduce thermal expansion coefficient mismatch and consequent stress fracture and that the performance of different materials can be simulated by Fatigue Analysis and Load.

Design and Simulation of a Micromachined CMOS Temperature Sensor

2009 ◽  
Vol 60-61 ◽  
pp. 334-338
Author(s):  
Hong Yu Ma ◽  
Qin Gan Huang ◽  
Ming Qin
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Low Cost ◽  
Wheatstone Bridge ◽  
Cmos Process ◽  
Piezoresistive Effect ◽  
Working Principle ◽  
Thermal Expansion Coefficient Mismatch ◽  
Mismatch Effect

A design and simulation of a fully CMOS compatible micromachined multilayer cantilevers-based environmental thermometer are presented. The operation principle of the structure is depending on the mismatch effect of thermal expansion coefficient and the piezoresistive effect of polysilicon in CMOS process. Upon temperature variation, the deformation of the multilayer cantilever resulted from the large thermal expansion coefficient mismatch of different materials can be sensed and translated to an electrical voltage output by using a symmetric piezoresistive Wheatstone bridge. The mechanical characteristics of the device are analyzed with the extension of bi-layer Timoshenko model and the output of the read-out circuit is also simulated. The calculation and simulation show that the device with bi-direction deformation may have wide temperature range from -100 to 100°C and sensitivity about 0.15mV/°C, which fit the demand of radiosonde for environmental temperature measurement. This sensor may also have other favorable features, such as micro size, low-cost due to its working principle and compatibility with commercial CMOS process.

scholarly journals Thermal expansion coefficient of few-layer MoS2 studied by temperature-dependent Raman spectroscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhongtao Lin ◽  
Wuguo Liu ◽  
Shibing Tian ◽  
Ke Zhu ◽  
Yuan Huang ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Negative Thermal Expansion ◽  
Thermal Parameter ◽  
Temperature Dependent ◽  
Bending Vibrations ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

AbstractThe thermal expansion coefficient is an important thermal parameter that influences the performance of nanodevices based on two-dimensional materials. To obtain the thermal expansion coefficient of few-layer MoS2, suspended MoS2 and supported MoS2 were systematically investigated using Raman spectroscopy in the temperature range from 77 to 557 K. The temperature-dependent evolution of the Raman frequency shift for suspended MoS2 exhibited prominent differences from that for supported MoS2, obviously demonstrating the effect due to the thermal expansion coefficient mismatch between MoS2 and the substrate. The intrinsic thermal expansion coefficients of MoS2 with different numbers of layers were calculated. Interestingly, negative thermal expansion coefficients were obtained below 175 K, which was attributed to the bending vibrations in the MoS2 layer during cooling. Our results demonstrate that Raman spectroscopy is a feasible tool for investigating the thermal properties of few-layer MoS2 and will provide useful information for its further application in photoelectronic devices.

EFFECTS OF THERMAL EXPANSION COEFFICIENT MISMATCH ON STRUCTURE AND ELECTRICAL PROPERTIES OF TiO2 FILM DEPOSITED ON Si SUBSTRATE

2008 ◽  
Vol 15 (04) ◽  
pp. 487-491 ◽  
Author(s):  
CHEN YANG ◽  
HUIQING FAN ◽  
SHAOJUN QIU ◽  
YINGXUE XI ◽  
JIN CHEN
Keyword(s):  
Thermal Expansion ◽  
Electrical Properties ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Ion Beam ◽  
Electron Beam Evaporation ◽  
Si Substrate ◽  
Cte Mismatch ◽  
Deposited Film ◽  
Thermal Expansion Coefficient Mismatch

Effects of thermal expansion coefficient (CTE) mismatch on structure and electrical properties of TiO 2 film deposited on Si substrate by ion beam assistant electron beam evaporation have been investigated. Because of a high CTE mismatch between TiO 2 film and Si substrate, microcracks appeared in the TiO 2 film deposited directly on Si substrate after the as-deposited film was annealed at 600°C. In order to decrease the CTE mismatch, TiO 2 film was deposited on Si substrate which was covered by a ZrO 2 thin layer. As a result, crack–free TiO 2 film after annealed at the same temperature was obtained. Meanwhile, corresponding to the crack–free structure, the TiO 2 thin film has more stable dielectric properties and excellent I–V characteristics.

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