title: Gate Controlled Photocurrent Generation Mechanisms in High-Gain In₂Se₃ Phototransistors.
abstract: Photocurrent in photodetectors incorporating van der Waals materials is typically produced by a combination of photocurrent generation mechanisms that occur simultaneously during operation. Because of this, response times in these devices often yield to slower, high gain processes, which cannot be turned off. Here we report on photodetectors incorporating the layered material In2Se3, which allow complete modulation of a high gain, photogating mechanism in the ON state in favor of fast photoconduction in the OFF state. While photoconduction is largely gate independent, photocurrent from the photogating effect is strongly modulated through application of a back gate voltage. By varying the back gate, we demonstrate control over the dominant mechanism responsible for photocurrent generation. Furthermore, because of the strong photogating effect, these direct-band gap, multilayer phototransistors produce ultrahigh gains of (9.8 ± 2.5) × 10(4) A/W and inferred detectivities of (3.3 ± 0.8) × 10(13) Jones, putting In2Se3 among the most sensitive 2D materials for photodetection studied to date.
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology , Lorentzweg 1, 2628 CJ Delft, The Netherlands.
authors.forename: J O
authors.initials: JO
authors.lastname: Island
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology , Lorentzweg 1, 2628 CJ Delft, The Netherlands.
authors.forename: S I
authors.initials: SI
authors.lastname: Blanter
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology , Lorentzweg 1, 2628 CJ Delft, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Buscema
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology , Lorentzweg 1, 2628 CJ Delft, The Netherlands.
authors.forename: H S J
authors.initials: HS
authors.lastname: van der Zant
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology , Lorentzweg 1, 2628 CJ Delft, The Netherlands.|Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-nanociencia), Campus de Cantoblanco , E-28049 Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Castellanos-Gomez
keywords: FET; In2Se3; high gain; indium selenide; mechanism; photodetector