Observation and characterization of impact ionization-induced OFF-state breakdown in Schottky-type p-GaN gate HEMTs

ABSTRACTOrganic-inorganic junctions were formed between porous silicon and various conjugated conducting polymers, poly(3-methylthiophene) and polypyrrole. Schottky type barriers were observed between the conducting polymers in their doped state and p and n-type porous silicon. In their undoped state the conducting polymers behave like p-type semiconductors. Consistent with this, ohmic contacts were observed between undoped conducting polymers and p-type porous silicon while rectifying behavior typical of a p-n junction was observed for conducting polymers deposited onto n-type porous silicon. During characterization of the porous silicon substrate, an investigation of the surface chemistry revealed a strong correspondence between solution pH and the luminescence intensity of porous silicon. Surface titration experiments were performed on p and n-type porous silicon and the results indicate that a monoprotic surface acid with a pKa between 3–4 is a primary component in the luminescence mechanism of porous silicon.

Download Full-text

Electrical Characterization of the Grain-Boundary Region of SnO2 Varistors

Materials Science Forum ◽

10.4028/www.scientific.net/msf.518.235 ◽

2006 ◽

Vol 518 ◽

pp. 235-240 ◽

Cited By ~ 1

Author(s):

M. Žunić ◽

Z. Branković ◽

G. Branković ◽

D. Poleti

Keyword(s):

Electrical Properties ◽

Grain Boundary ◽

Electric Fields ◽

Electrical Characterization ◽

Boundary Region ◽

Current Voltage ◽

Schottky Type ◽

Boundary Properties ◽

Current Voltage Characteristics

The effect of Co, Cr and Nb on the electrical properties of the grain boundaries of SnO2-based varistors was investigated. The powders were prepared by the method of evaporation and decomposition of solutions and suspensions. Varistor samples were obtained by uniaxial pressing followed by sintering at 1300 °C for 1h. The electrical properties of the grain-boundary region, such as resistance (R) and capacitance (C), were determined using ac impedance spectroscopy in the 27-330 °C temperature interval. Activation energies for conduction (EA) were calculated from the Arrhenius equation. The non-linear coefficients (α) and the breakdown electric fields (Eb) of the samples were determined from the current-voltage characteristics. The potential barrier height (Φb) was calculated using the Schottky-type conducting model. After a comparison of the characteristic parameters for different varistor compositions it was found that the Cr/Nb ratio has a crucial influence on the grain-boundary properties in SnO2 varistors.

Download Full-text

Characterization of InP electron-initiated impact ionization in low electric fields using abrupt junction NpN InP/GaAsSb/InP double heterojunction bipolar transistors

Applied Physics Letters ◽

10.1063/1.1637446 ◽

2003 ◽

Vol 83 (26) ◽

pp. 5548-5550 ◽

Cited By ~ 1

Author(s):

S. Lam ◽

C. R. Bolognesi ◽

S. P. Watkins

Keyword(s):

Electric Fields ◽

Heterojunction Bipolar Transistors ◽

Impact Ionization ◽

Bipolar Transistors ◽

Double Heterojunction ◽

Abrupt Junction

Download Full-text

Quantum-chemical calculations of the products and energies of electron induced ionization of 2-Furanmethanol, Tetrahydro-and 3-Furanol

Facta universitatis - series Physics Chemistry and Technology ◽

10.2298/fupct0801127p ◽

2008 ◽

Vol 6 (1) ◽

pp. 127-139 ◽

Cited By ~ 7

Author(s):

P. Papp ◽

P. Mach ◽

J. Urban ◽

S. Matejcík

Keyword(s):

Ab Initio ◽

Electron Impact ◽

Quantum Chemical Calculations ◽

Quantum Chemical ◽

Impact Ionization ◽

Theoretical Treatment ◽

Ab Initio Methods ◽

Conformational Studies ◽

Fragmentation Patterns

A theoretical treatment is used to perform conformational studies of title compounds, which was previously successfully used within our group for characterization of fragmentation patterns of some bio-molecules. Now we present studies of electron impact ionization of 2 Furanmethanol, Tetrahydro (C5H10O2) and 3-Furanol, Tetrahydro (C4H8O2), both as important models for more complicated compounds like nucleic acids. In this paper geometry of the neutral and cationic conformers of these two molecules was optimized on the DFT level with B3LYP functional, and ionization energies were estimated. DFT calculated results are supplemented with G3MP2 calculations, and a set of higher-level ab initio methods were empirically corrected to obtain more reliable results.

Download Full-text