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The low frequency current and light intensity noise of the next generation light emitting diodes (LEDs) with wavelengths ranging from 265 to 340 nm is reported. The relative spectral noise density of the light intensity fluctuations decreased with an increase of the LED forward current and at high currents, the difference in the noise level for LEDs with different wavelength is small and is of the same order of magnitude or even smaller than for visible LEDs.

The variable stripe length (VSL) method is used to investigate the optical gain in GaN epilayers. Gain peak values up to ~7500 [cm.sup.-1] is shown in GaN epilayers grown on AIN buffer layers deposited on sapphire by migration enhanced metal-organic chemical vapor deposition.

The plasma oscillation spectrum in high-electron mobility transistors (HEMTs) with recessed gate having the highly doped caps adjacent to the source and drain contacts and the windows between the caps and the gate is calculated. The effect of cap region could result in a significant reduction of the resonant frequencies in comparison with those calculated for simplified HEMT model.

The low frequency noise in GaN/AlGaN heterostructure field effect transistors (HFETs) was studied in the temperature range from 8 to 300 K. The position of the maximum was practically independent of the frequency of analysis.

Low frequency noise was investigated in GaN metal semiconductor and metal oxide semiconductor field effect transistors.

A low frequency noise model for degenerate semiconductors is presented, revealing noise level dependence on band to band illumination.

Two-dimensional electron gas transport in elementary semiconductors was investigated.

Gate leakage current effects on noise in A1GaN/GaN field effect transistors are examined.

Organic thin film transistors of different designs were modeled.

Pentacene organic thin film transistors were studied with regard to the flicker (1/f) noise.

A new study investigates low-frequency noise in gallium nitride/gallium-aluminum nitride field effect transistors grown on silicon carbide and sapphire substrates.

Low-frequency noise in n-type gallium nitride (GaN) deposited on sapphire with electron mobility of 790 square cm/V s at 300 K has been measured. Results indicate that the level of flicker noise in GaN is highly dependent on the structure of the material. The effects of band-to-band illumination on the low-frequency noise indicate that 1/f noise in GaN may result from the occupancy fluctuations of the tail states near the band edges.

The breakdown behavior of a heterodimensional two-dimensional MESFET has been investigated. It is a novel side-gated FET made from a double-sided planar-doped AlGaAs/InGaAs PHEMT material. Its on-state breakdown behavior reduces impact ionization at high drain-source bias leading to a low output conductance of less than 6 mS/mm for V(sub GS) = 0 V and a low gate leakage current of less than 100 nA. Its off-state drain-source and drain-gate breakdown voltages were measured to be at 20 and 21 V.

A strong piezoresistive effect was detected in AlN-GaN shrot-range superlattices. The measured static gauge factor ranged from 30 to about 90 depending on the superlattice composition. These values were much bigger than the values of the gauge factor reported for GaN-AlN-GaN semiconductor-insulator-semiconductor structures. Findings illustrate a strong potential for AlN-GaN-based materials for the development of piezoelectric and piezoresistive sensors.

A double-channel AlGaN/GaN heterostructure field-effect transistor (HFET) was proposed for high power applications, where the bottom channel was formed by a GaN/AlGaN/GaN semiconductor-insulator-semiconductor structure. Charge distribution and the band structure were strongly affected by the piezoelectric effect caused by the mismatch between AlGaN and GaN. This design demonstrated that the carrying capability of AlGaN/GaN HFETs can be enhanced using multichannel structures.

Low frequency fluctuations in light intensity were measured from five different types of commercially available light emitting diodes with wavelengths from 375 nm to 740 nm and from two different halogen lamps. At low frequencies below 10-100 Hz some light emitting diodes (LEDs) can provide lower levels of noise than halogen lamps. A noise quality factor Β is proposed in order to characterize noise behavior of LEDs. [DOI: 10.1063/1. [ABSTRACT FROM AUTHOR]

The scanning near field optical spectroscopy technique is employed to explain the optical properties and performance of the AlGaN quantum well based deep ultraviolet light emitting diodes. The aging process of the diodes is shown to be highly dependent on the presence of N vacancies in the system.

Several studies are conducted to explain the impact of the forward current stress on the low frequency noise exhibited by the different 4H-SiC p-n junctions. The stress is shown to lead to the onset of the burst noise in these junctions.

Terahertz (THz) lasers on optically pumped multiple-graphene-layer (MGL) structures as their active region are described. The model has accounted for the interband and intraband transitions in the degenerate electron-hole plasma generated by optical radiation in the MGL structure and the losses in the slot or dielectric waveguide.

The analysis of the data following the McWhorter model for the low frequency noise in amorphous Si thin film transistors (TFTs) with Si[N.sub.x] gate dielectric has shown relatively low density of traps. The value is close to the lower limit for amorphous and polycrystalline Si TFTs and the trap density has increased with the increase of the gate voltage.

The low frequency noise is analyzed in 4H-SiC metal oxide semiconductor filed effect transistors (MOSFETs) in the frequency range from 1 Hz to 100 kHz. The energy dependence of trap density responsible for the noise is extracted for the states located close to the bottom of conduction band.

A device model is developed for a resonant detector of electromagnetic radiation with a frequency in the terahertz (THz) range modulated by megahertz (MHz) or gigahertz (GHz) signals based on a micromachined high-electron mobility transistor (HEMT) with a metallized nanostring (NS) or metallic carbon nanotube (CNT) as the mechanically floating gate. The studies have shown that the THz detector responsivity has displayed sharp and high maxima under the conditions of both mechanical and plasma resonances.