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The magnetic-field effect on electroluminescence (EL) has been investigated for the tris-(8-hydroxyquinolino) aluminum (Alq3)-based organic light emitting diode. The EL intensity sharply increases up to 8% with increasing magnetic field to 500 Oe at room temperature. The magnetic field effect on EL depends on the interface structure between a hole transporting and a light emitting layers, indicating the importance of the spin-state dynamics of the electron-hole pairs at the interface. [ABSTRACT FROM AUTHOR]

A homogeneous, amorphous peroxopolytungstic acid film can be formed easily with the spin-coating method. The film is found to provide a homogeneous tungsten metal film after reduction with hydrogen at ∼400 °C. Although the electric resistivity (∼450 μΩ cm) is higher than that for the bulk (5.65 μΩ cm), this method has an advantage in addition to spin coatability: tungsten metal films with fine patterns can be easily obtained because the starting material is photosensitive. [ABSTRACT FROM AUTHOR]

Voltage-controlled optical bistable laser operation is demonstrated for the first time using nonlinear optical absorption of two-dimensional excitons in a GaAs-AlGaAs multiple quantum well (MQW) laser. The laser used here is the conventional MQW laser diode but with tandem electrode configuration. The L-I curve of light output as a function of current injected into one segment of electrodes can be changed by a bias voltage applied to the other segment of electrodes. At the onset of laser oscillation, a hysteresis loop appears, the shape of which depends strongly on the applied bias voltage. This bistability is ascribed to the nonlinear absorption of two-dimensional excitons. [ABSTRACT FROM AUTHOR]

Recently reported amorphous polytungstic acids containing peroxo groups are found to provide a new inorganic resist. A homogeneous resist film can be formed easily with the spin coating method. This film is made insoluble in water by deep ultraviolet, x ray, and electron beam irradiation. The oxygen reactive ion etching (O2 RIE) durability is found to be high enough that a bilayer resist scheme employing this resist as a top imaging layer gives a high resolution pattern (line and space: 0.38 μm). The mechanism for the radiation induced reaction is also discussed. [ABSTRACT FROM AUTHOR]

This letter describes the monolithic integration of a laser diode and an optical waveguide modulator that have the same GaAs/AlGaAs quantum well double heterostructure grown on the same substrate. The intensity of the light emitted from the laser diode is modulated by the modulator, utilizing the effect of an electric field on exciton absorption. The absorption loss coefficient of the modulator waveguide with no applied voltage was estimated to be 60 cm-1. This value is much smaller than the previously reported corresponding value of a veguide having a conventional GaAs double heterostructure. The modulation depth achieved was 7 dB for a driving voltage of 2.3 V; the cut-off modulation frequency was 0.88 GHz. A prospect for improving these characteristics is also presented. [ABSTRACT FROM AUTHOR]

Optical pulses of less than 4 ps full width at half maximum have been generated by electrical gain switching of long-wavelength multiple quantum well lasers, and were observed directly on a streak camera. This is the first ever generation of optical pulses of such short duration using direct electrical gain switching. We have identified the higher differential gain due to the second quantized state transition in the multiple quantum well laser to be responsible for the generation of these ultrashort optical pulses. We also discuss the possible resolution limits of the streak camera measurement system. [ABSTRACT FROM AUTHOR]