Van der Waals Multi‐Heterostructures (PN, PIN, and NPN) for Dynamic Rectification in 2D Materials

Abstract

Here, van der Waals multi‐heterojunctions (PN, NP, PIN, and NPN) are fabricated by stacking of MoTe2, hexagonal boron nitride (h‐BN), and MoSe2 nanoflakes using a mechanical‐exfoliation technique where the dynamic rectification is examined. Low‐resistance metal contacts Al/Au and Pt/Au are applied to MoSe2 and MoTe2, respectively, and gate‐dependent rectifying behavior is achieved, with a rectification ratio of up to 105 in PN devices. It is found that the performance of the device is enhanced by placing an interfacial layer h‐BN between two opposite layers of 2D materials where the rectification ratio is found to be >106 with the ideality factor ≈1.3 in the PIN devices. Also, using the conventional Richardson's plot, the barrier heights of PN and PIN diodes are calculated to be 260 and 490 meV at zero gate bias, respectively. As well, the devices exhibit good performance with a built‐in electric field observed in both PN and PIN diodes, which gives rise to an open‐circuit voltage (Voc) and short‐circuit current (Isc) under zero external bias. Remarkably, it is found that the performance of the devices also gets better by forming double heterojunction (NPN) layer than PN or NP layers. The device is also tested for a rectification application, and it successfully rectifies an input alternating‐current signal. These findings are important for the development of nano‐ and optoelectronics devices.

Highly Efficient, Surface Ligand Modified Quantum Dot Light‐Emitting Diodes Driven by Type‐Controllable MoTe2 Thin Film Transistors via Electron Charge Enhancer

“…As a result, a clear type conversion of MoTe 2 TFTs without degradation of electrical properties was obtained, and both n‐type and p‐type MoTe 2 TFTs demonstrated a stable QLED‐operation. This successful type conversion result can be effectively utilized to realize the fundamental and important device application based on MoTe 2 such as p–n diode and complementary inverters, [ 28–33 ] without structural change or additional layer. Moreover, fabricated MoTe 2 TFTs exhibited excellent suppression of photocurrents under UV–near‐infrared (NIR) region, showing a unique advantage for the applications such as display backplane transistors as well as light‐to‐frequency conversion circuits, as compared to other TMDCs and conventional Si materials.…”

Effect of an optimal oxide layer on the efficiency of graphene‐silicon Schottky junction solar cell

“…The macromolecular PFSA doping is very helpful in optimizing the electrical properties of graphene 31‐34 . The doping of PFSA enhances the work function of graphene which results in a decrease in recombination current that is reverse current due to minority charge carriers 35 as demonstrated in Figure 5A,B. This causes an increase in hole concentration and decreases in electron concentration proportionally.…”

Recent progress in the role of two‐dimensional materials as an efficient charge transport layer in perovskite solar cells

“…This mineral was initially discovered by a Russian scientist Lev Perovski and hence the name perovskite is assigned for it. 15,16 The perovskite materials are generally described by the formula ABX 3 , where A and B are cations such that the size of A is larger than B and X is an anion. Most of the work on perovskite-based PV devices is aimed at organometal tri-halide perovskites, wherein A symbolizes the organic cation, B represents the metal cation, and X denotes the halide anion.…”

“…The TMDCs like MoS 2, MoSe 2, WS 2 , WSe 2 , PtSe 2 , and MoTe 2 have revealed outstanding optical, [30][31][32][33][34] and mechanical 29,[35][36][37][38] electronic properties. 3,15,16 Similarly, graphene, a stable 2D material with a hexagonal structure, has produced a significant impact in real-world applications due to its astonishing chemical and physical properties. [17][18][19] The high transparency, excellent electrical transport, and virtuous carrier mobility make graphene a notable contestant for transparent electrode and carrier transport layer in SCs.…”