Effect of temperature dependence ultrasonic velocities and attenuation of GaP nanowires

Pramod Kumar Yadawa

doi:10.1007/s40094-016-0216-x

Abstract

The higher order elastic constants of the hexagonal wurtzite crystal structure of GaP nanowires have been evaluated using Lennard-Jones potential model at room temperature. The ultrasonic velocity increases with the temperature along particular orientation with the unique axis of crystals. Temperature variation of the thermal relaxation time and Debye average velocities is also calculated along the same orientation. The temperature dependency of the ultrasonic properties is discussed in correlation with elastic, thermal and electrical properties. It has been found that the thermal conductivity is the main contributor to the behaviour of ultrasonic attenuation as a function of temperature and the responsible cause of attenuation is phonon–phonon interaction. The mechanical properties of GaP nanowires at low temperature are better than at room temperature, because at low temperature it has low ultrasonic velocity and ultrasonic attenuation. A particularly interesting case is GaP, which is the only (Ga, In)-V semiconductor with an indirect gap in the bulk phase, and are indispensable in modern microelectronic industries.

Highlights

In present times, novel crystal structures in III–V semiconductor nanowires (NWs) have generated immense scientific interest
The second order elastic constants are used for the determination of the ultrasonic attenuation and related parameters
As our calculated results for elastic constants reasonably satisfy aforesaid criteria for the gallium phosphide (GaP) nanowires which indicate that this nanowire is mechanically stable

Summary

Introduction

Novel crystal structures in III–V semiconductor nanowires (NWs) have generated immense scientific interest. Ultrasonic attenuation is very important physical parameter to characterize the material, which is well related to several physical quantities like thermal conductivity, specific heat, thermal energy density and higher order elastic constants [17]. Has not been addressed yet, in present work we predict the ultrasonic properties of GaP nanowires at different temperatures. The ultrasonic attenuation coefficient, acoustic coupling constants, higher order elastic constants, thermal relaxation time and ultrasonic wave velocities for GaP for unique direction of propagation of wave are calculated as a function of temperature.

Results

Conclusion