Manganese oxide (MnO₂) is a promising material for supercapacitor applications, with a theoretical ultra-high energy density of 308 Wh/kg. However, such ultra-high energy density has not been achieved experimentally in MnO₂-based supercapacitors because of several practical issues, such as low electrical conductivity of MnO₂, incomplete utilization of MnO₂, and dissolution of MnO_2. The present study investigates the potential of MnO₂/reduced graphene oxide (rGO) hybrid nanoscroll (GMS) structures as electrode material for overcoming the difficulties and for developing ultra-high-energy storage systems. A hybrid supercapacitor, comprising MnO₂/rGO nanoscrolls as anode material and activated carbon (AC) as a cathode, is fabricated. The GMS/AC hybrid supercapacitor exhibited enhanced energy density, superior rate performance, and promising Li storage capability that bridged the energy–density gap between conventional Li-ion batteries (LIBs) and supercapacitors. The fabricated GMS/AC hybrid supercapacitor demonstrates an ultra-high lithium discharge capacity of 2040 mAh/g. The GMS/AC cell delivered a maximum energy density of 105.3 Wh/kg and a corresponding power density of 308.1 W/kg. It also delivered an energy density of 42.77 Wh/kg at a power density as high as 30,800 W/kg. Our GMS/AC cell’s energy density values are very high compared with those of other reported values of graphene-based hybrid structures. The GMS structures offer significant potential as an electrode material for energy-storage systems and can also enhance the performance of the other electrode materials for LIBs and hybrid supercapacitors.

This study proposes an ultrathin tellurium (Te) atomic layer deposition process with a TeO _x seed layer to overcome large electrical hysteresis. It also identifies causes of defects, aiding high-performance p-type inorganic transistors.

A novel approach to delicately control the phase of a ferroelectric has been developed using a continuous-wave laser scanning annealing (CW-LSA) process. After proper process optimization, the equivalent oxide thickness (EOT) of 3.5 Å with a dielectric constant (κ) of 68 Å is achieved from HZO in a metal-ferroelectric-metal (MFM) capacitor structure. The leakage current density (J_g = 4.6 × 10^-5 A/cm² at +0.8 V) was four times lower compared to the reference group treated with an optimized RTA process. The outstanding electrical characteristics of the 6 nm HZO film were attributed to the stable formation of the morphotropic phase boundary (MPB) structure, which was enabled by the directional scanning nature of the CW-LSA process.

Electroforming-free resistive switching random access memory (RRAM) devices employing magnesium fluoride (MgF_x) as the resistive switching layer are reported. The electroforming-free MgF_x based RRAM devices exhibit bipolar SET/RESET operational characteristics with an on/off ratio higher than 10² and good data retention of >10⁴ s. The resistive switching mechanism in the Ti/MgF_x/Pt devices combines two processes as well as trap-controlled space charge limited conduction (SCLC), which is governed by pre-existing defects of fluoride vacancies in the bulk MgF_x layer. In addition, filamentary switching mode at the interface between the MgF_x and Ti layers is assisted by O–H group-related defects on the surface of the active layer.

This study investigates the switching characteristics of the silicon oxynitride (SiO_xN_y)-based bipolar resistive random-access memory (RRAM) devices at different operating ambiances at temperatures ranging from 300 K to 77 K. The operating ambiances (open air or vacuum) and temperature affect the device’s performance. The electroforming-free multilevel bipolar Au/Ni/SiO_xN_y/p⁺-Si RRAM device (in open-air) becomes bilevel in a vacuum with an on/off ratio >10⁴ and promising data retention properties. The device becomes more resistive with cryogenic temperatures. The experimental results indicate that the presence and absence of moisture (hydrogen and hydroxyl groups) in open air and vacuum, respectively, alter the elemental composition of the amorphous SiO_xN_y active layer and Ni/SiO_xN_y interface region. Consequently, this affects the overall device performance. Filament-type resistive switching and trap-controlled space charge limited conduction (SCLC) mechanisms in the bulk SiO_xN_y layer are confirmed.