Nonlinear Optical Defect Detection

Improving the performance and downsizing the carrier channels in semiconductor and electro-optics devices has faced the obstacle of power dissipation. New materials like III-V with higher carrier velocity for these channels are attractive as they can operate at lower voltage and avoid the energy and information loss. Growing these materials such as GaAs or InP over mismatch Si substrate leave us with variety of defects including threading dislocations which act as sink or scattering points for electrons. For the first time a fast and noninvasive nonlinear optical technique has been used to map the localization of the light by these defects which act as effective cavity for scattering light. We demonstrate how in nonlinear regime, presence of dislocation defects can be revealed in sub-micron hotspot looking domains collected by nearfield scanning optical microscope (NSOM) system. Films over different substrate with variety of dislocation defects density has been studied and comparison has been done with invasive technique such as cross STEM imaging.