Bell Telephone Laboratories

At&t Bell Laboratories

Benjamin Tell

Sigurd Wagner

Horst Manfred Kasper

Wayne Harvey Knox

Ted Kirk Woodward

Jason Blain Stark

Gary D Boyd

Robert E Nahory

Fred Wudl

Yong H Lee

Sarat K Mohapatra

Photocurrent suppression is achieved without deleteriously affecting modulation performance in a surface normal, electro-absorption, quantum well modulator by introducing a sufficient number of non-radiative recombination centers in the quantum well region of the modulator. The presence of the non-radiative recombination centers significantly shortens the lifetime of photogenerated carriers and, thereby, suppresses the photocurrent. Modulation performance characteristics such as contrast ratio are maintained at acceptable levels even though exciton broadening occurs in the quantum wells. The present modulator exhibits a careful balance between defect density in the quantum wells and the acceptable degree of exciton broadening necessary to preserve quantum effects.

Suppressed photocurrent, quantum well optical modulation device

Top surface emitting, vertical cavity, surface emitting lasers depend upon emission through apertured top surface electrodes. Biasing current, accordingly peripheral to the laser as introduced, follows a path which comes to confluence within the active gain region to effectively attain lasing threshold. The path is consequence of a buried region of increased resistance which encircles the laser at or above the active region. The buried region is produced by ion implantation-induced damage with ion energy magnitude and spectrum chosen to produce an appropriate resistance gradient. Integrated, as well as discrete, lasers are contemplated.

Top-emitting surface emitting laser structures

A method of growing a water insoluble native plasma oxide on an In.sub.0.53 Ga.sub.0.47 As layer of the type that is useful in the fabrication of MOS type devices is disclosed. Oxygen is bubbled through a water chamber in order to introduce water vapor into the growth chamber during the growing process. The InGaAs layer is first sputter etched in the oxygen plasma while a negative potential is applied to the semiconductor structure. The pressure is then increased and the oxides are grown while a positive potential is applied to the semiconductor structure.

Method of growing oxide layer on indium gallium arsenide

Solid state electrochromic devices are fabricated using, as the electrochromic material, ionic conductors such as heteropoly acids. The properties of the ionic conductors permit construction of a device having only two electrodes and the electrochromic material. In operation, low voltages impressed between the electrodes induce a color change. For example, when phosphotungstic acid is employed, the color change is from white to dark blue. Cycle times as low as 100 msec are achievable and the devices exhibit memory properties.

Solid electrochromic devices

Ionic conductivity in ternary chalcogenides of the form AB.sub.x C.sub.y, where A is a metallic atom with atomic number no greater than 55 which has a +1 oxidation state, B is a group III A metallic atom and C is a group VI A atom, has been observed. This ionic conductivity makes the compounds useful as components in electrochemical cells, e.g., electrolytes and electrodes.

Growing community of inventors

Matawan, NJ, United States of America

Benjamin Tell