Performance Analysis of Optically Gated MoS2 Photosensor for Visible Light Detection

Photodetectors are of utmost importance in optoelectronics, and the rising multiplicity of technology calls for new materials and novel device paradigms. This work proposes an optically gated double-gate tunnel field-effect transistor photosensor, employing a monolayer of transition metal dichalcogenide as the channel material. The photodetector works on the principle of band-to-band tunneling, which, we demonstrate, is capable of detecting visible range of wavelength 300–1100 nm at as low intensities as
${0.5}~\text {W/cm}^{{2}}$
. The photogenerated voltage is developed upon illumination of light, and it has been modeled to illustrate the device’s operation. The sensor can obtain a photosensitivity and responsivity of around
$~{10}^{{4}}$
and quantum efficiency
$\gt {50}$
% for an incident intensity of
${0.5}~\text {W/cm}^{{2}}$
and wavelength of 700 nm. The work further discusses the effects of dielectric material and demonstrates the high value of photosensor parameters when a combination of
$\text {HfO}_{{2}}$
and
$\text {SiO}_{{2}}$
is used as dielectric materials in the photosensor. In addition, we explore the impact of the dimensions and positioning of the illumination window. It has been perceived that increased thickness and overlap of the illumination window with the source result in improved performance parameters. Finally, the benchmarking of the proposed double-gate tunnel field-effect transistors (TFETs) photosensor is done against the state of the art.