Laser-induced selective area band-gap tuning in Si/Si1-xGex microstructures

A one-step process is reported for selective area band-gap tuning of as-gro wn quantum well (QW) material consisting of Si/Si1-xGex microstructures. Th e process takes advantage of the ability of increasing the local temperatur e of the wafer, in excess of 900 degrees C, by applying the beam of a high- power cw Nd:YAG laser, which leads to controlled intermixing between the qu antum well and barrier material. A microstructure with the band-gap blueshi fted by 142 meV has been fabricated from as-grown 980 meV band-gap material . The results indicate that this approach has the potential for "writing'' of Si/Si1-xGex QW microstructures with the selectively tuned band gap requi red in the fabrication of optoelectronic integrated circuits. (C) 1999 Amer ican Institute of Physics. [S0003-6951(99)04314-4].