Modification of Semiconductors for Monolithic Integration of Optoelectronic Devices

Altair Center proposes to develop a revolutionary new technology for room temperature selective modification of semiconductor materials adjusting bandgap, strain, refractive index and quantum-confined properties of the semiconductor structures alreadyafter their growth. The selective processing of the semiconductor materials employs a novel process of modification assisted by illumination of the semiconductor with a laser beam. In Phase I of the project we investigated such semiconductor materials asGaAs and InP, and demonstrated that the process of modification changes chemical composition in the near-surface region of the material and eventually creates nanoclusters (quantum dots) in the semiconductor dramatically changing its electromagneticproperties, refractive index and adjusting bandgap. In phase II of the project the demonstrated modification technology will be optimized and applied to fabrication of basic semiconductor-based components critical for monolithic integration ofoptoelectronic device. The large index change can be employed for fabrication of a broad class of semiconductor-based active or passive components using simple direct laser beam writing. These components include relief-free waveguide structures,micoresonators, diffractive grating and diffractive optical elements with high index contrast. The grating having period of the order of wavelength and sufficiently large index contrast may exhibit photonic bandgap structure, resulting in new photoniccrystals with unique properties. In addition to immediate military applications, the proposed technology is an excellent candidate for fabrication of different photonic and diffractive optical products in several markets, including: opticalcommunicaitons, WDM and signal processing, diffractive grating, computer generated holograms, spatial light modulators, diode lasers, photonic bandgap structures, thin film photvoltaic devices, etc.