Effect of temperature dependence ultrasonic velocities and attenuation of GaP nanowires

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.