A visible-light phototransistor based on the heterostructure of ZnO and TiO₂ with trap-assisted photocurrent generation

Abstract

Visible-light phototransistors have been fabricated based on the heterojunction of zinc oxide (ZnO) and titanium oxide (TiO2).

Boosting the Visible Light Optoelectronic Synaptic Characteristics of Solution-Processed IGZO Transistors via Vertically Diffused Cd Dopants

“…As is widely known, the oxygen vacancies form an additional state at the near VBM region. Therefore, oxygen vacancies could generate photocurrent onto the conduction band by absorbing relatively lower photon energy of visible light wavelength. , Various methods, such as doping polymers, mechanochemical treatments, or forming heterostructures, have been explored to enhance the detection characteristics of visible light using oxygen vacancies. ,,− However, these methods often result in reduced electrical characteristics of the device, such as a transistor. Since our IGZO:Cd TFTs exhibited highly enhanced electrical characteristics and increased amounts of oxygen vacancies, we have adopted them as phototransistors.…”

Highly enhanced visible light photodetection properties of a ZnO phototransistor via an additional solution processed thin Al2O3 layer

“…The increased intensity indicates that more oxygen vacancies exist in ZnO when the Al 2 O 3 layer was added, which is in consistence with the XPS results. 30,31 The work function of Al 2 O 3 and ZnO was measured to be 2.74 eV and 3.00 eV, respectively. However, the work function value of ZnO was increased to 3.57 eV when ZnO was formed above the thin Al 2 O 3 layer.…”

Characteristics of PEALD–Hafnium Dioxide Films and their Application to Gate Insulator Stacks of Photosynaptic Transistors

“…When visible light (1.8 eV < E < 3.1 eV, lower than the bandgap; here, E represents bandgap) was incident on the TiO 2 films with a bandgap of 3.2 eV, the increase in the current was caused by the generation of carriers with a trap-to-band transition rather than a band-to-band transition. [51] Furthermore, the holes were trapped in the shallow trap sites, shifting the transfer curves to the left after the light irradiation. In this case, after the light irradiation, the curves returned to their initial state over time when the samples were exposed to air.…”