Cross-plane thermal conductivity temperature dependence for PbSnSe/PbSe thin film superlattice material from 100K to 300K

ABSTRACTThe temperature dependence of cross-plane lattice thermal conductivity for thin film IV-VI semiconductors grown by molecular beam epitaxy was measured. Samples consisting of PbSe/PbSrSe multiple quantum wells (MQWs) on PbSe/PbSnSe superlattices (SLs) were grown with variations in SL layer thickness and the number of SL pairs. Localized lattice temperatures within the MQW layers were extracted from analysis of continuous wave photoluminescence (PL) emission spectra at heat sink temperatures between 100 K and 250 K. These data, finite element analysis, and electrical characterization were used to determine cross-plane lattice thermal conductivity of two different SL materials. A SL material with three different PbSe/PbSnSe thicknesses (1.2/1.2, 1.8/1.8, and 2.4/2.4 nm) exhibited a fairly constant lattice thermal conductivity from 1.2 to 1.3 W/mK as the sample was cooled from 250 K to 100 K. Another SL material with five different PbSe/PbSnSe thicknesses (0.5/0.5, 1.0/1.0, 1.6/1.6, 2.1/2.1, and 2.6/2.6 nm) exhibited very low lattice thermal conductivities from 0.46 to 0.47 W/mK 250 K to 100 K. These results are consistent with reflection of low energy heat transporting acoustic phonons within the SL material.

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MBE-Grown IV-VI Semiconductor Structures for Thermal Conductivity Measurements

MRS Proceedings ◽

10.1557/opl.2012.473 ◽

2012 ◽

Vol 1404 ◽

Author(s):

Patrick J. McCann ◽

Leonard Olona ◽

Zhihua Cai ◽

James D. Jeffers ◽

Khosrow Namjou

Keyword(s):

Thermal Conductivity ◽

Molecular Beam ◽

Lattice Thermal Conductivity ◽

Continuous Wave ◽

Multiple Quantum Well ◽

Multiple Quantum ◽

Element Analysis ◽

Light Emitting ◽

Semiconductor Structures ◽

Viable Approach

ABSTRACTIV-VI semiconductor structures grown by molecular beam epitaxy (MBE) have been used to measure the cross-plane thermal conductivity of PbSe and PbSe/PbSnSe/PbSe multiperiod superlattice (SL) materials. Continuous wave photoluminescence (PL) measurements were used to determine epilayer temperatures localized to multiple quantum well (MQW) light emitting layers on top of various IV-VI materials structures. These data combined with finite element analysis (FEA) were used to extract cross-plane thermal conductivity values for different materials designs. Structures consisting of PbSe/PbSnSe/PbSe SL materials with multiple periodicities exhibited cross-plane lattice thermal conductivity values as low as 0.30 W/mK, a significant reduction relative to the 1.9 W/mK value for bulk PbSe. This work shows that lattice thermal conductivity reduction offers a highly viable approach for improving thermoelectric materials performance.

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Onset of size effects in lattice thermal conductivity and lifetime of low-frequency thermal phonons

MRS Proceedings ◽

10.1557/opl.2012.269 ◽

2012 ◽

Vol 1404 ◽

Author(s):

A.A. Maznev

Keyword(s):

Thin Film ◽

Thermal Conductivity ◽

Size Effects ◽

Lattice Thermal Conductivity ◽

Low Frequency ◽

Square Root ◽

Relaxation Rates ◽

Frequency Limit ◽

Conductivity Of Thin Films ◽

Closed Form Formula

ABSTRACTThe onset of size effects in phonon-mediated thermal transport along a thin film at temperatures comparable or greater than the Debye temperature is analyzed theoretically. Assuming a quadratic frequency dependence of phonon relaxation rates in the low-frequency limit, a simple closed-form formula for the reduction of the in-plane thermal conductivity of thin films is derived. The effect scales as the square root of the film thickness, which leads to the prediction of measurable size-effects even at “macroscopic” distances ~100 μm. However, this prediction needs to be corrected to account for the deviation from the ω−2 dependence of phonon lifetimes at sub-THz frequencies due to the transition from Landau-Rumer to Akhiezer mechanism of phonon dissipation.

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Temperature Dependence and Reflection of Coherent Acoustic Phonons in InGaN Multiple Quantum Wells

physica status solidi (b) ◽

10.1002/1521-3951(200111)228:1<85::aid-pssb85>3.0.co;2-s ◽

2001 ◽

Vol 228 (1) ◽

pp. 85-89 ◽

Cited By ~ 2

Author(s):

�. �zg�r ◽

C.-W. Lee ◽

H.O. Everitt

Keyword(s):

Quantum Wells ◽

Temperature Dependence ◽

Multiple Quantum Wells ◽

Multiple Quantum ◽

Acoustic Phonons ◽

Coherent Acoustic Phonons

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Temperature Dependence of Photoresponse in p-Type GaAs/AlGaAs Multiple Quantum Wells: Theory and Experiment

MRS Proceedings ◽

10.1557/proc-607-187 ◽

1999 ◽

Vol 607 ◽

Author(s):

F. Szmulowicz ◽

A. Shen ◽

H. C. Liu ◽

G. J. Brown ◽

Z. R. Wasilewski ◽

...

Keyword(s):

Quantum Wells ◽

Temperature Dependence ◽

Bound States ◽

Light Hole ◽

Multiple Quantum ◽

Temperature Dependent ◽

Long Wavelength ◽

Hole Level ◽

Polarization Characteristics ◽

P Type

AbstractThis paper describes a study of the photoresponse of long-wavelength (LWIR) and mid-infrared (MWIR) p-type GaAs/AlGaAs quantum well infrared photodetectors (QWIPs) as a function of temperature and QWIP parameters. Using an 8x8 envelope-function model (EFA), we designed and calculated the optical absorption of several bound-to-continuum (BC) structures, with the optimum designs corresponding to the second light hole level (LH2) coincident with the top of the well. For the temperature-dependent study, one non-optimized LWIR and one optimized MWIR samples were grown by MBE and their photoresponse and absorption characteristics measured to test the theory. The theory shows that the placement of the LH2 resonance at the top of the well for the optimized sample and the presence of light-hole-like quasi-bound states within the heavy-hole continuum for the nonoptimized sample account for their markedly different thermal and polarization characteristics. In particular, the theory predicts that, for the LWIR sample, the LH-like quasi-bound states should lead to an increased Ppolarized photoresponse as a function of temperature. Our temperature dependent photoresponse measurements corroborate most of the theoretical findings with respect to the long-wavelength threshold, shape, and polarization and temperature dependence of the spectra.

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Temperature Dependence of Thermal Conductivity of Amorphous and Crystal Thin Film by Molecular Dynamics Simulation

ASME 5th International Conference on Nanochannels, Microchannels, and Minichannels ◽

10.1115/icnmm2007-30085 ◽

2007 ◽

Cited By ~ 1

Author(s):

Zhengxing Huang ◽

Zhenan Tang ◽

Suyuan Bai ◽

Jun Yu

Keyword(s):

Thin Film ◽

Thin Films ◽

Thermal Conductivity ◽

Integrated Circuits ◽

Temperature Dependence ◽

Amorphous Materials ◽

Dynamics Simulation ◽

Amorphous Sio2 ◽

Film Boundary ◽

Different Temperatures

For crystal materials, thermal conductivity (TC) is proportional to T3 at low temperatures and to T−1 at high temperatures. TCs of most amorphous materials decrease with the decreasing temperatures. If a material is thin film, boundary will influence the TC and then influence the temperature dependence. In this paper, we calculate the TC of crystal and amorphous SiO2 thin films, which is a commonly used material in micro devices and Integrated Circuits, by NEMD simulations. The calculation temperatures are from 100K to 700K and the thicknesses are from 2nm to 8nm. TCs of crystal thin films reach their peak values at different temperatures for different thicknesses. The smaller thickness the larger peak values obtained. But for amorphous thin films, the results show that the temperature dependence of thin films is the same as bulk materials and not relative to their thicknesses. The obtained temperature dependence of the thin films is consistent with some previous measurements and the theory predictions.

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