Strain-Enhanced Photovoltaic Effect in MoTe2

The recent development of two-dimensional (2D) materials has demonstrated that by using the bulk photovoltaic effect (BPVE) for crystals lacking inversion symmetry, it is possible to overcome the Shockley-Queisser limit. So far, the exploration of 2D p-n junction designs have recently been extensively investigated. However, the mechanism of BPVE differs from traditional p-n junction-based photovoltaics in 2D materials. This paper presents the first experimental demonstration of the bulk photovoltaic effect in 1T '-MoTe2. The measured intensity dependence V-oc and I-sc display a direct relationship to the incident light (power: 20 to 120 W cm(-2); wavelengths: 400, 450, 500 nm). In 1T '-MoTe2 nanoflakes on flexible polyimide, astrain-enhanced BPVE is seen, producing a BPVE response of 3.60 mV. In addition, the BPVE tensor value increased from 259 to 527 A W-1 for unstrained 1T '-MoTe2 while it increased from 467 to 882 A W-1 for strained 1T '-MoTe2 as the wavelength decreased from 500 to 400 nm. The results show a new way to improve the efficiency of turning energy into electricity in new optoelectronic materials.