Modulation of the Al/Cu₂O Schottky Barrier Height for p-Type Oxide TFTs Using a Polyethylenimine Interlayer

Abstract

We introduced an organic interlayer into the Schottky contact interface to control the contact property. After inserting an 11-nm-thick polyethylenimine (PEI) interlayer between the aluminum (Al) source/drain electrode and the cuprous oxide (Cu2O) channel layer, the Cu2O thin-film transistors (TFTs) exhibited improved electrical characteristics compared with Cu2O TFTs without a PEI interlayer; the field-effect mobility improved from 0.02 to 0.12 cm2/V s, the subthreshold swing decreased from 14.82 to 7.34 V/dec, and the on/off current ratio increased from 2.43 × 102 to 1.47 × 103, respectively. Careful investigation of the contact interface between the source/drain electrode and the channel layer established that the performance improvements were caused by the formation of electric dipoles in the PEI interlayer. These electric dipoles reduced the Schottky barrier height by neutralizing the charges at the metal/oxide semiconductor interface, and the holes passed the reduced Schottky barrier by means of tunneling or thermionic injection. In this way, p-type oxide TFTs, which generally need a noble metal having a high work function as an electrode, were demonstrated with a low-work-function metal. As a basic application for logic circuits, a complementary inverter based on n-type indium–gallium–zinc oxide and p-type Cu2O TFTs was fabricated using only Al source/drain electrodes. This research achieved advances in low-cost circuit design by broadening the electrode metals available for the manufacture of p-type oxide semiconductor-based electronics.

Interface molecular wires induce electron transfer from COFs to Pt for enhanced photocatalytic H2 evolution

“…The stable sandwich structure prevents PtNPs from coming into contact with TpPa-1. It promotes the formation of electric dipoles in the SC interlayer, thus reducing the SBH 34,35 (Fig. S17b †).…”

Homojunction Interface Boosts Hole-Carrier Injection in p-Type CuI Nanoribbon Field-Effect Transistors

“…In the homojunction device, lower SBH and V FB values of 70 meV and 48 V, respectively, were observed compared to the pristine device, with SBH and V FB values of 107 meV and 61 V. Moreover, Figure f presents a contour plot effectively illustrating the observed thermionic emission and tunneling regions in the homojunction CuI NR FET, with V FB (dotted line in Figure f) distinguishing both regions. These findings indicate that the homojunction CuI NR FET exhibits a lower barrier height when compared to the pristine CuI NR FETs, leading to reduced contact resistance and interfacial trap density for efficient charge transfer. − …”

Intriguing interfacial characteristics of the CS contact with MX2 (M = Mo, W; X = S, Se, Te) and MXY ((X ≠ Y) = S, Se, Te) monolayers

“…One can see that Φ B,p have higher values than Φ B,n , thus, the CS–MX 2 (M = Mo, W; X = S, Se, Te) and CS–MXY ((X ≠ Y) = S, Se, Te) (in both model-I and -II) vdWH form p-type Schottky contacts. These p-type Schottky contacts can be considered to be a promising building block for high-performance photoresponsive optoelectronic devices, 89 p-type electronics, 90 CS–based contacts, 91 and for high-performance electronic devices. 92 While making the CS–MX 2 (M = Mo, W; X = S, Se, Te) and CS–MXY ((X ≠ Y) = S, Se, Te) vdWH, there is no chemical bond among CS and MX 2 (MXY) layers, which may create an interface dipole, which can be calculated via the potential step Δ ρ , as presented in Fig.…”