Sensor behavior of MoS2 field-effect transistor with light injection toward chemical recognition.

Md Iftekharul Alam,Tsuyoshi Takaoka,Atsushi Ando,Tadahiro Komeda,Muhammad Shamim Al Mamun,Hiroki Waizumi,Yudai Tanaka

doi:10.1039/d1ra03698j

Abstract

The application of field-effect transistor (FET) devices with atomically thin channels as sensors has attracted significant attention, where the adsorption of atoms/molecules on the channels can be detected by the change in the properties of FET. Thus, to further enhance the chemical sensitivity of FETs, we developed a method to distinguish the chemical properties of adsorbates from the electric behavior of FET devices. Herein, we explored the variation in the FET properties of an MoS2-FET upon visible light injection and the effect of molecule adsorption for chemical recognition. By injecting light, the drain current (Id) increased from the light-off state, which is defined as (ΔId)ph. We examined this effect using CuPc molecules deposited on the channel. The (ΔId)phvs. wavelength continuous spectrum in the visible region showed a peak at the energy for the excitation from the highest occupied orbital (HOMO) to the molecule-induced state (MIS). The energy position and the intensity of this feature showed a sensitive variation with the adsorption of the CuPc molecule and are in good agreement with previously reported photo-absorption spectroscopy data, indicating that this technique can be employed for chemical recognition.

Highlights

There is a great demand for miniaturized sensors, which enable the on-chip integration of sensors, and analyses/processes can be applied for their operation under in vivo conditions.[1,2,3] For such an application, the eld-effect transistor (FET) sensor using atomically thin channel can be a promising candidate
The MoS2-based field-effect transistor (FET) used in this experiment showed the transfer characteristics illustrated as the blue solid line in Fig. 2, which showed the typical n-type semiconductor behavior
In the case of the second reason, we previously reported that a large difference appeared between the Id–Vg curves obtained in air and under ultra-high vacuum (UHV) condition.[15]

Summary

Introduction

There is a great demand for miniaturized sensors, which enable the on-chip integration of sensors, and analyses/processes can be applied for their operation under in vivo conditions.[1,2,3] For such an application, the eld-effect transistor (FET) sensor using atomically thin channel can be a promising candidate. We examined this effect of coper phthalocyanine (CuPc) deposited on the channel of an FET device and the FET properties were measured, focusing on the photo-induced drain current vs l spectra.

Results

Conclusion