Bias Tunable Photocurrent in Metal-Insulator-Semiconductor Heterostructures with Photoresponse Enhanced by Carbon Nanotubes

Abstract

Metal-insulator-semiconductor-insulator-metal (MISIM) heterostructures, with rectifying current-voltage characteristics and photosensitivity in the visible and near-infrared spectra, are fabricated and studied. It is shown that the photocurrent can be enhanced by adding a multi-walled carbon nanotube film in the contact region to achieve a responsivity higher than 100 mA W−1 under incandescent light of 0.1 mW cm−2. The optoelectrical characteristics of the MISIM heterostructures are investigated at lower and higher biases and are explained by a band model based on two asymmetric back-to-back Schottky barriers. The forward current of the heterojunctions is due to majority-carrier injection over the lower barrier, while the reverse current exhibits two different conduction regimes corresponding to the diffusion of thermal/photo generated carriers and majority-carrier tunneling through the higher Schottky barrier. The two conduction regimes in reverse bias generate two plateaus, over which the photocurrent increases linearly with the light intensity that endows the detector with bias-controlled photocurrent.

Zinc Gallium Oxide—A Review from Synthesis to Applications

“…The narrowing of the depletion region allowed the electrons to tunnel easily in the left MS, resulting in the enhancement of photoconductive gain under DUV illumination. In addition, the band model of the Schottky barrier with the forward and reverse bias has been clearly described and proposed by Bartolomeo et al, which can be found in Reference [92].…”

A Current–Voltage Model for Double Schottky Barrier Devices

“…to account for the rectifying electrical characteristics observed in field effect transistors with ultrathin transition‐metal dichalcogenide channel [ 6,7 ] or in metal/insulator/semiconductor structures. [ 8 ]…”

WS2 Nanotubes: Electrical Conduction and Field Emission Under Electron Irradiation and Mechanical Stress

“…CNTs have attracted particular attention due to the ease of production through multiple methods and the possibility to achieve both metallic and semiconducting NTs, depending on their chirality and diameter. [ 4–9 ] However, the difficulty in selecting the desired CNT properties during the production process, commonly leading to a mixture of metallic and semiconducting CNTs in the final product, makes their use in technological applications an open challenge. In recent years, inorganic layered materials, such as MoS 2, [ 10–13 ] PdSe 2, [ 14–16 ] WSe, [ 17,18 ] WS 2 , [ 19 ] and GeAs [ 20 ] have been widely studied for their unique electrical and optical properties.…”