Time resolved surface analysis (kinetic and molecular time scales): general discussion

Abstract

Wendy Flavell opened a general discussion of the paper by Martina Dell'Angela: You have very nicely separated out two separate timescales for the dynamics in this system. In the context of the SPV, clearly this scales with uence, but (quite apart from the 'n/p' issue) naively I wondered if you expect to see an SPV shi at all in this systemit seems to be fairly two-dimensional to medoes it have a depletion layer at the surface that could give rise to an SPV shi?Martina Dell'Angela answered: We thank you for the question. MoTe 2 is indeed a 2D layered material, but we are measuring a bulk crystal in the 2H phase, which is a semiconductor. Interlayer interactions are weak in this class of material, but the out-of-plane conductivity is not entirely suppressed (around 10 3 times lower than the in-plane conductivity), thus allowing for the formation of a depletion region and for the rise of photovoltage effects, as observed in other transition metal dichalchogenides, e.g., MoS 2 (ref. 1 and 2) and WSe 2 . 3