Direct evidence of spontaneous quantum dot formation in a thick InGaN epilayer.

We report a direct observation of quantum dots formed spontaneously in a thick InGaN epilayer by high resolution transmission electron microscopy. Investigation of a (280 nm thick) In[sub 0.22]Ga[sub 0.78]N single layer, emitting in the blue/green spectral region, reveals quantum dots with estimated sizes in the range of 1.5-3 nm. Such sizes are in very good agreement with calculations based on the luminescence spectra of this specimen. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]