Effect of temperature dependence ultrasonic velocities and attenuation of GaP nanowires

The higher order elastic constants of thehexagonal wurtzite crystal structure of GaP nanowires havebeen evaluated using Lennard-Jones potential model atroom temperature. The ultrasonic velocity increases withthe temperature along particular orientation with the uniqueaxis of crystals. Temperature variation of the thermalrelaxation time and Debye average velocities is also calculatedalong the same orientation. The temperaturedependency of the ultrasonic properties is discussed incorrelation with elastic, thermal and electrical properties. Ithas been found that the thermal conductivity is the maincontributor to the behaviour of ultrasonic attenuation as afunction of temperature and the responsible cause ofattenuation is phonon–phonon interaction. The mechanicalproperties of GaP nanowires at low temperature are betterthan at room temperature, because at low temperature it haslow ultrasonic velocity and ultrasonic attenuation. A particularlyinteresting 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.