Dr. Heinrich Gottlob, VISHAY Semiconductor GmbH, Theresienstr. 2, 74072 Heilbronn, Germany
The physics of silicon photodetector diodes is discussed with respect to spectral sensitivity. While silicon offers a broad spectral sensitivity range including human eye range especially its near infrared sensitivity challenges the ambient light sensor designer. Application examples are given for standard and advanced ambient light sensors from VISHAY´s optoelectronic device portfolio. Spectral sensitivity engineering is demonstrated by package based filters or on chip interference filters.
Winfried Mönch, Fakultät für Physik, Universität Duisburg-Essen
The band-structure lineup at semiconductor interfaces is explained by the continua of intrinsic interface-induced gap states (IFIGS) that derive from the complex band structures of the semiconductors. The barrier heights of metal-semiconductor or Schottky contacts as well as the band-edge offsets of semiconductor heterostructures are composed of a zero-charge-transfer term plus an electrostatic-dipole contribution which are determined by the branch-point energies of the semiconductors and the electronegativity difference of the two materials in contact, respectively. It will be demonstrated that the IFIGS-and-electronegativity concept rather than the Schottky-Mott rule also explains the experimental barrier heights reported for graphene Schottky contacts.
Graphene Pressure and Gas Sensors for More than Moore Applications
Fabrication of graphene based pressure and gas sensors has been achieved. Analysis into the devices’ characteristics has been undertaken – yielding a number of promising properties that may make graphene a competitive material for use in future more than Moore applications.
Statistical Analysis of Graphene Field Effect Transistors
A graphene transfer method has been established on wafer scale and large scale device characterization and subsequent statistical data analysis has been performed. The combination of statistical methods coupled with large scale fabrication, automated characterization and computational analysis lead to massive increases in efficiency and deeper insight into device behavior.
Since its discovery in 2004, graphene has been considered as one of the most promising materials for applications in nanoelectronics as it is a real two-dimensional (2D) crystal. This atomic thick crystal enables electrons to have extremely high carrier mobility (up to 105 cm2/Vs) by suppressing lattice scattering. The atomic layer is absolutely elastic but at the same time the atoms involved in sp2-hybridized bonds in the crystal yield the most robust structure which has a physical strength that is about 100 times higher than steel. Exploiting such extraordinary properties, state-of-the-art graphene devices including the gigahertz-range transistors, sensitively functioning sensors, transparent-flexible devices, and wearable applications have been demonstrated. However, the development of graphene devices as logic components is undermined due to the nature of the zero bandgap in graphene. Although a bilayer or graphene nanoribbon can open a few-hundred-meV energy gap, its breakthrough technology is challenging to implement.