Spatially resolved photolumiescence

Set-up description

Room and low temperature spatially resolved micro-photoluminescence is used to investigate our structures. The exciting laser beam is focused on the sample by microscope, providing a spot diameter of the order 1 mm (this value is determined by diffraction limit of objective). The penetration depth of the laser beam should be high enough to achieve the optically active region of multilayer structure. In the most cases we used He-Ne or Ar+ lasers, depending on the kind of investigated structure. The sample lays on the stage integrated with scanning module: X-Y stages combined width two mechanical encoders. The measurement points form square mesh covered the investigated area on the sample. The step distance between neighboring measurement points may even be less than 1 mm. The LN2 cooled CCD camera collects whole spectrum for each examined point. However, the saving and processing such a huge amount of data is difficult, so each spectrum is numerically processed and only the main signatures of the PL feature are saved: the integrated PL intensity and the spectral position of maximum. In this way we obtain the set of maps with characteristic parameters of investigated area. The full measurement cycle takes from few minutes up to even tens hours, depending on the investigated area size and spatial resolution of measurement.


PL set-up and screen-shots of PL mapping system PMS 2000 control panel



PL set-up

Available excitation sources:

Sources Wavelength (nm)
Ar+ 333,6
363,8
454,5
457,9
465,8
472,7
476,5
488,0
496,5
501,7
514,5
528,7
He-Cd 442
He-Ne
 632,8
Ti:Sapphire  tunable: 680 - 1100





whole wafer

Investigating of integrated PL intensity and the spectral position of maximum PL distribution on the typical 2-inch wafer - step 500mm


defect on GaAs

Investigating of defects in the GaAs layer - step 5 mm