Photoelectric Memory Effect in Graphene Heterostructure Field-Effect Transistors Based on Dual Dielectrics

Abstract

We report a photo and field (PF)-induced doping of a graphene-heterostructure field-effect transistor (graphene HFET) using a double-layered gate insulator consisting of narrow-bandgap insulator (NGI) and widebandgap insulator (WGI). The PF-induced doping in the graphene HFETs with variable NGIs (hafnium oxide, silicon nitride, and hexagonal boron nitride) are investigated, and consequently we reveal that this rewritable/erasable doping behavior is not limited to specific insulating materials, but unexceptionally accomplished when a step-like vertical band diagram, that is graphene/NGI/WGI, is fulfilled in the device. We clearly verify that this doping is originated from PF-induced charge transfer between graphene and defects at the NGI/WGI interface, and then the polarized charges at the NGI/WGI interface pretend to be "remote dopants", shifting Dirac voltage of the device. The remote dopant is highly stable in the dark due to the presence of the adjacent insulators providing enormous energy barriers, but can be efficiently tuned by the modulation of the gate bias and incident photon energy. Because the PF-induced doping mechanism is not limited by specific materials that is still hard to be synthesized as a large scale, the graphene HFET memory devices can be patterned with a large scale using practical fabrication processes, appealing to industrial applications.

A Tunneling Dielectric Layer Free Floating Gate Nonvolatile Memory Employing Type‐I Core–Shell Quantum Dots as Discrete Charge‐Trapping/Tunneling Centers

“…The memory window with ±130 V sweep range is only 9 V. It is widely acknowledged that the hysteresis of a transistor originates from the charge trapping–detrapping process in or around the conductive channel . The hysteresis of the none‐QD device can be ascribed to the unintentional damage to graphene during the transfer process, and the doping effect of PMMA on graphene . The huge hysteresis of the ZnSe@ZnS‐OA QDs device should be mainly attributed to the existence of the ZnSe@ZnS‐OA QDs.…”

Recent Advances in the Bias Stress Stability of Organic Transistors

“…In addition to these results for rubrene single‐crystal OFETs, the photoinduced bias stress effect has been examined in diverse material systems including a tetracene single crystal, a tetraphenylbis(indolo{1,2‐ a })quinoline single crystal, a pentacene thin film, a dinaphtho[2,3‐b:2',3'‐f]‐thieno[3,2‐b]thiophene thin film, and a polythiophene thin film . Such photoinduced charge transfer could be an advantage in improving the optical sensitivity of phototransistors or in optically programmed memory devices . In contrast to the photoinduced bias stress effect, illumination without gate biasing can result in a releasing‐bias stress effect, which is the recovery of V th and I D to their pre‐stressed values .…”

Nonvolatile Rewritable Frequency Tuning of a Nanoelectromechanical Resonator Using Photoinduced Doping

“…In the erased state, is offset from zero by ~1 V, which is common and indicates the presence of static charged contaminants. With = 30 V, saturates to ~28 V, where the new potential arises from charged defects in the h-BN 19,21 and the oxide 20 . Although differs by ~27 V between the two states, the gate-dependence of each mode relative to doesn't change, as seen in Figure 1d-e.…”

“…Here, we demonstrate a persistent, rewritable, scalable, and high-speed frequency tuning method for graphene-based NEMS [15][16][17][18] . Our method uses a focused laser and two shared electrical contacts to photodope [19][20][21][22] individual resonators by simultaneously applying optical and electrostatic fields. After the…”

“…In this letter, we report reversible and long-lived frequency tuning of graphene and graphene/hexagonal boron nitride (hBN) NEMS membrane resonators. Our technique uses spatially resolved photodoping [19][20][21][22] , requiring only a focused laser and a global gate voltage 𝑉 𝑔 , to generate rewritable, trapped charges. These charges create a local potential that shifts the mechanical charge neutrality point 29 from its intrinsic value (near 0 V) to 𝑉 𝑚𝐶𝑁𝑃 .…”