Modulation doped quantum well waveguide modulator

US5535045A · kind A · utility

Assignee

• The United States of America as represented by the Secretary of the Army · US

Inventors

• Mitra Dutta · Tinton Falls, US
• Weimin Zhou · Rockville, US

Key dates

• Filing date: Mar 17, 1994
• Grant date: Jul 9, 1996
• Expiry date: Mar 17, 2014

Classification

• Technology area (CPC G): Physics
• CPC primary: G02F1/01708
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

The dielectric constant and the optical properties of a semiconductor device are changed by tuning the electron density in modulation doped quantum wells. The quantum wells are formed in an "i" region of a p-i-n structure having, in sequence, a 150 .ANG. wide GaAs quantum well, a wider Al.sub.x Ga.sub.1-x As barrier with a central silicon doped section and an undoped AlGaAs barrier with a slightly higher barrier height to prevent transfer of carriers to the next well. When a reverse bias is applied, more D centers are tuned below the Fermi level so that they can trap electrons from the wells, thereby reducing electron density and changing the optical properties of the material.