Note: A modified optics based technique for suppressing spurious signals in photoreflectance spectra.

A modified optics based technique was developed to effectively suppress spurious background signals encountered in the photoreflectance (PR) spectra obtained from bulk semiconductors and semiconductor microstructures. Based on a traditional PR setup, the novel PR approach utilized an achromatic beam reduction system to narrow the profile of a probe beam, which was subsequently collected by a focus lens coupled with an iris. The new setup guarantees high collection efficiency for probe signals and strong suppression of background signals. Compared with existing PR methods for background minimization, the proposed PR technique is simpler to accomplish, more cost effective, and provides a higher signal-to-noise ratio for the PR spectra.