It is seen that the photo-responsivity for blue (450вЂ‰nm) and red (650вЂ‰nm) light is few orders of magnitude higher than near infrared (IR) (850вЂ‰nm) light. We also report very high photo-responsivity of ~10 5вЂ‰A/W under forward bias 1.5вЂ‰V at room temperature. This unique observation can be explained by including interlayer recombination rate of charge carriers along with the individual layer response. 15, 16, 17, 18, 19, 20, 21 We further show that the magnitude and the position of the dip in I DSвЂ“ V BG curve can be modulated by changing the incident power density of light. Interestingly, the I DS as a function of back gate voltage ( V BG) show an unusual dip at the highest conductance value on top of the usual antiambipolar nature. bias ( V DS) data show the characteristics of a pвЂ“n junction. In this work, we have carried out electrical and photo-conductivity measurements of vertical heterostructures made of a few-layers MoTe 2 (~6 layers) and single-layer MoS 2. 25 The band engineering of vertical heterostructures 26 with available TMDs having different band gaps and work functions have paved the way to investigate the charge transport mechanisms in atomically thin pвЂ“n junction. 6, 25 This tunneling at the interfaces is predicted to be governed by Shockley-Read-Hall (SRH) or by Langevin recombination mechanisms. Here, transport occurs via tunneling of carriers from one layer to the other layer. 15, 16, 17, 18, 19, 20, 21 However, pвЂ“n junction made of single layer of TMDs, known as atomically thin pвЂ“n junctions, 22, 23, 24, 25 show quite different type of charge transport mechanism compared to the conventional pвЂ“n junction. These TMD-based vertical heterostructures have shown potentials as pвЂ“n junction and most of these pвЂ“n junctions show antiambipolar transconductance behavior. 11, 12 Atomically sharp interfaces with intralayer high carrier mobility and lack of dangling bonds result in unique spatial charge separation 13 between the layers, as well as produce long-lived interlayer excitons 14 under light exposure. In recent years, van der Waals (vdW) heterostructures based on transition metal dichalcogenides (TMDs) are being studied extensively, due to their excellent electronic and opto-electronic properties 1, 2, 3, 4 with potential applications such as transistor, 5 photo detector, 6, 7 light-emitting diode (LED), 8, 9, 10 and solar cells. Our findings may pave the way for better understanding of atomically thin interface physics and device applications. The similar dip is also observed in the transmission spectrum when calculated using density functional theoryвЂ“non-equilibrium GreenвЂ™s function formalism. We further develop first principles-based atomistic model to explore the charge carrier transport through MoTe 2вЂ“MoS 2 heterojunction. We explain these new findings based on interlayer recombination rate-dependent semi-classical transport model. We also demonstrate high photo-responsivity of ~10 5вЂ‰A/W at room temperature for a forward bias of 1.5вЂ‰V. We further observe that the modulation of the dip in the transconductance depends on the doping concentration of the two-dimensional flakes and also on the power density of the incident light. Over and above the antiambipolar transfer characteristics observed similar to other hetero pвЂ“n junction, our experiments reveal a unique feature as a dip in transconductance near the maximum. In this article, we present the fabrication, electrical, and opto-electrical characterization of vertically stacked few-layers MoTe 2(p)вЂ“single-layer MoS 2(n) heterojunction. The control and tunability of the interlayer carrier transport in these pвЂ“n junctions have a potential to exhibit new kind of electronic and optoelectronic devices. Fabrication of the out-of-plane atomically sharp pвЂ“n junction by stacking two dissimilar two-dimensional materials could lead to new and exciting physical phenomena.

Light response study in quantumwise