Klar provides a test and measurement service for scientists and engineers studying the surface topography, composition, defects, fracture lines, and other features of their materials and structures. Autofocus scans of photoluminescence spectra in the visible-near IR may be obtained over areas ranging from sq. microns to sq. cm. Examples of our micro-PL spectra and our mapping capabilities are displayed below. Just write to us at klar@klarscientific.com so we may arrange for a mini-project with you to test the sample, discuss the data with you, and return the data and the sample in a timely manner.

Micro-PL

In a PL measurement, a laser is focused onto the surface of a semiconductor sample, exciting electrons across the band gap. When the electrons fall to lower energies, they emit light that is characteristic of the band gap or defect centers.

PL illustration.jpg

Micro-PL is especially useful for samples with weak emission or rough surfaces that scatter light. As shown in the figure below, a standard spectrometer was unable to obtain a signal.

PL spectra from the  Klar micro-PL  and a standard (non-microscope) fluorescence spectrometer. The main peak is band-edge luminescence and the sideband at 900 nm is emission from a defect level. Sample provided by Mike Scarpulla (University of Utah) and Chris Ferekides (University of South Florida).

PL spectra from the Klar micro-PL and a standard (non-microscope) fluorescence spectrometer. The main peak is band-edge luminescence and the sideband at 900 nm is emission from a defect level. Sample provided by Mike Scarpulla (University of Utah) and Chris Ferekides (University of South Florida).

PL mapping

A PL map is produced by scanning the sample and taking a spectrum at each (x,y) point. The PL peak or intensity is represented by a color. Klar microscopes can map tiny samples or large wafers, with high spatial resolution. 

(a) PL spectra from a “2D” α-In2Se3 layer and α-In2Se3/β-In2Se3 junction. (b) PL peak energy map of the junction device. After Wang et al.,  J. Phys. Chem. Lett.   8 , 2887 (2017).

(a) PL spectra from a “2D” α-In2Se3 layer and α-In2Se3/β-In2Se3 junction. (b) PL peak energy map of the junction device. After Wang et al., J. Phys. Chem. Lett. 8, 2887 (2017).