Search

The high κ ZrAlO x gate insulators were deposited by atomic layer deposition on silicon and characterized by the different analytical techniques. The grazing incidence X-ray diffraction (GIXRD) verifies that ZrAlO x thin films show an amorphous structure. The X-ray photoelectron spectroscopy (XPS) confirms that the form of ZrAlO x phase improves the electrical properties and stability of the associated devices. Then, all ZrAlO x thin films were integrated in metal-insulator-semiconductor structures to check the electrical capabilities. They all show a low leakage current density (about 1 × 10 −8 A/cm 2 ) under a high electric field of about 2.0 MV/cm, and exhibit a stable capacitance as a function of frequency. Their associated ZTO TFTs were deposited by a radio frequency sputtering, and the influence of the ZrAlO x thickness on the stabilities under positive bias stress and electrical properties is investigated. The 130 nm ZrAlO x based TFT shows the optimized electrical properties (its mobility, threshold voltage, sub-threshold voltage swing and on-off ratio are 12.5 cm 2 /V, 0.3 V, 0.15 V/dec. and 8 × 10 7 and the good stability with 2.5 V threshold voltage shift under the positive bias voltage stress. The better properties of 130 nm ZrAlO x based TFTs are attributed to a less interface trap states and surface scattering center. [ABSTRACT FROM AUTHOR]

In this work, we report the influence of ZnSnO channel layer sputtering power in the stability of ZnSnO TFTs under negative gate-bias illumination stress (NBIS). The origin of threshold voltage shift results from combined effect of two factors between the little defect-induced trap densities originated from oxygen vacancies and better channel–insulator interface. The kinetic energy of the ions at a proper rf sputtering power is responsible for less defect-induced trap density and better channel–insulator interface. Therefore, the ZnSnO TFT fabricated at 75 W sputtering power shows a better NBIS stability. In addition, the trap density is extracted by temperature-dependent field-effect measurements and it is consistent with the change of stability under NBIS and thermal stress. [ABSTRACT FROM AUTHOR]

We investigate the stability of thin film transistors incorporating sputtered InZnO as the channel layer under negative bias illumination stress. The transfer characteristic for various active layer thicknesses is shifted toward the negative direction under negative bias illumination stress and the device with thicker channel layer shows a slighter V TH negative shift than another device under negative bias illumination stress. In order to investigate channel layer thickness can have a great effect on the trap density and thus affect the V TH shift caused by charge trapping; we use temperature-dependent field-effect measurements method to accurately calculate their trap density. The results show that thicker InZnO channel layer has fewer DOSs, resulting in the decrease of charge trapping and the decrease of photoexcitation generated electron carrier. So the device with thicker channel layer shows a slighter V TH negative shift than another device under negative bias illumination stress. [ABSTRACT FROM AUTHOR]

We theoretically study graphene-based ferromagnet/insulator/ p -wave superconductor hybrid structure, where an anomalous zero bias conductance peak (ZBCP) is exhibited. With the exchange field h increased, the zero-bias conductance dips (ZBCDs) for both the p x - and p y -wave situations develop into ZBCPs at h ∕ E F > 1 , which are just contrary to the situation at h ∕ E F < 1. Furthermore, with the enhancement of barrier strength χ , the conversion from the ZBCD to ZBCP is displayed in the region of h ∕ E F > 1 for the p x -wave, whereas the sharp ZBCP remains all the time at any h for the p y -wave. More interestingly, the zero-bias conductance for the p x -wave keeps unchanged upon increasing χ , while for the p y -wave, exhibits periodical modulation of χ. The singular features can be used to not only identify the p -wave superconductivity and spin polarization in graphene but also pave the way to a new class of tunable superconducting spintronic devices based on large-scale graphene. • An anomalous zero bias conductance peak (ZBCP) is exhibited in this hybrid structure. • With the exchange field h increased at h ∕ E F > 1 , the zero-bias conductance dips (ZBCDs) for both the p x - and p y -wave situations develop into ZBCPs, which are just contrary to those for h ∕ E F < 1. • With the increase of χ , the conductance gets an enhancement at the edge (corresponding to e V ∕ Δ 0 = 1) for p x -wave SC junction, which is not exhibited for the p y -wave situation. [ABSTRACT FROM AUTHOR]

Abstract Boron doped InZnO (BIZO) thin film has been fabricated via solution process and the effect of boron addition on the properties of BIZO thin film is investigated with the glancing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), the atomic force microscopy (AFM) and UV–vis spectrophotometer. The XPS spectra show that the oxygen vacancies in IZO semiconductor materials are effectively suppressed by boron contents due to high Lewis acid strength and strong bonding dissociation energy of B O. Moreover, the associated application in TFTs has also been fabricated by solution process and the thermal stability and electrical properties of solution processed BIZO-TFTs are investigated to confirm the decrease of oxygen vacancies in IZO materials. Meanwhile, the capacitance voltage measurement and the density of states are carried out to further investigate the enhanced electrical performance and thermal stability of TFTs due to the suppression of oxygen vacancies. Thus, the B doping is an effective method to suppress the generation of oxygen vacancies in IZO materials and to improve the thermal stability of solution processed BIZO-TFTs. Highlights • Influence of boron composition on oxygen vacancy of BInZnO thin films. • Thermal stability of BInZnO TFTs. • Solution processed BIZO thin films and BIZO-TFTs. • CV measurement and the DOS. [ABSTRACT FROM AUTHOR]