Ultrafast and Sensitive Self-Powered Photodetector Featuring Self-Limited Depletion Region and Fully Depleted Channel with van der Waals Contacts

Abstract

Self-powered photodetectors with great potential for implanted medical diagnosis and smart communications have been severely hindered by the difficulty of simultaneously achieving high sensitivity and fast response speed. Here, we report an ultrafast and highly sensitive self-powered photodetector based on two-dimensional (2D) InSe, which is achieved by applying a device architecture design and generating ideal Schottky or ohmic contacts on 2D layered semiconductors, which are difficult to realize in the conventional semiconductors owing to their surface Fermi-level pinning. The as-fabricated InSe photodiode features a maximal lateral self-limited depletion region and a vertical fully depleted channel. It exhibits a high detectivity of 1.26 × 1013 Jones and an ultrafast response speed of ∼200 ns, which breaks the response speed limit of reported self-powered photodetectors based on 2D semiconductors. The high sensitivity is achieved by an ultralow dark current noise generated from the robust van der Waals (vdW) Schottky junction and a high photoresponsivity due to the formation of a maximal lateral self-limited depletion region. The ultrafast response time is dominated by the fast carrier drift driven by a strong built-in electric field in the vertical fully depleted channel. This device architecture can help us to design high-performance photodetectors utilizing vdW layered semiconductors.

Cross‐Substitution Promoted Ultrawide Bandgap up to 4.5 eV in a 2D Semiconductor: Gallium Thiophosphate

“…[ 13,14 ] In addition, 2D materials usually have atomic thickness, [ 15 ] high specific surface area, [ 16 ] and strong light‐matter interaction, [ 17 ] which can provide high responsivity and photoconductive gain in nanoscale photodetectors. [ 18–22 ] Such 2D materials currently cover a vast range of bandgaps from the terahertz in bilayer graphene, [ 23 ] visible in transition metal dichalcogenides to the ultraviolet in h‐BN and mica. [ 24 ] As the ultrawide bandgap, dielectric nature, and atomically flat surface, h‐BN and mica are usually served as a substrate for high‐mobility 2D devices.…”

“…[13,14] In addition, 2D materials usually have atomic thickness, [15] high specific surface area, [16] and strong light-matter interaction, [17] which can provide high responsivity and photoconductive gain in nanoscale photodetectors. [18][19][20][21][22] Such 2D materials Exploring 2D ultrawide bandgap semiconductors (UWBSs) will be conductive to the development of next-generation nanodevices, such as deep-ultraviolet photodetectors, single-photon emitters, and high-power flexible electronic devices. However, a gap still remains between the theoretical prediction of novel 2D UWBSs and the experimental realization of the corresponding materials.…”

A high performance self-powered photodetector based on a 1D Te–2D WS2 mixed-dimensional heterostructure

“…In general, the indirect bandgap of multilayered WS 2 and Te are 1.4 eV and 0.35 eV, respectively. Before contact, the conduction band minimum (CBM) of WS 2 and Te microwire are approximately -4.24 eV and -4.02 eV, respectively, and the corresponding valence band maximum (VBM) in WS 2 and Te microwire are approximately -5.64 eV and -4.37 eV, respectively[39,45]. The is 56.7…”

High‐Performance Near‐Infrared Photodetectors Based on Surface‐Doped InSe

“…[ 14–16 ] However, most studies on InSe‐based photodetectors have focused on the visible wavelength regime. [ 17–21 ] A few reports show InSe photodetectors sensing IR light, [ 22–27 ] but their performance is limited. [ 24–27 ] In this article, we report photodetectors based on AuCl 3 ‐doped InSe.…”