High temperature Raman investigation of few-layer MoTe2

We present a Raman investigation of the temperature effect of single and few layer MoTe2 at an electronic device working temperature range from 300 K to 500 K. We observe linear frequency red-shifts with increasing temperature for the first order Raman active E-2g(1), A(1g), Raman inactive B-2g(1) mode, and the second order omega(2) mode, which can be attributed to the anharmonic effect of the interatomic potential energy. The temperature coefficients of the out-of-plane vibrational B-2g(1) modes and inplane vibrational E-2g(1) modes are similarly around -0.013 cm(-1)/K, while lower than that of out-of-plane vibration A(1g) mode at -0.009 cm(-1)/K. The temperature coefficient of omega(2) mode is -0.00521 cm(-1)/K, approximately half of those of the first order modes, and the temperature coefficient of transverse acoustic TA (M) mode is indirectly deduced as -0.0102 cm(-1)/K, which shows the corresponding Mo-Te stretching bonds of TA (M) mode behavior similarly to those of optical Raman vibrations. Our work thus provides temperature dependent lattice vibration information of MoTe2 and could be potentially useful in future optoelectronic devices based on MoTe2 related two dimensional materials. (C) 2016 AIP Publishing LLC.