Nitride‐based quantum structures and devices on modified GaN substrates

Abstract

We have studied the properties of InGaN layers and quantum wells grown on gallium nitride substrates with intentional surface misorientation with respect to its crystalline c‐axis. Misorientation varied in the range from 0 up to 2 degree. The indium content was changed by using the different growth temperature (between 750 °C and 820 °C) during metalorganic vapor phase epitaxy. With increasing misorientation angle the average indium content decreased significantly. This effect was accompanied by the strong increase of the emission line bandwidth suggesting more pronounced indium segregation. The results of cathodoluminescence measurements show that these effects correspond to different number of atomic steps/terraces existing on the surface of gallium nitride substrate. Very interesting result is also demonstrated concerning p‐type GaN layers. With increasing misorientation, the free hole density drastically increases above 1018 cm–3. This improvement in p‐type doping is not related to the increased Mg concentration but to the reduction in the compensating donor density. Using this advantage we demonstrate nitride light emitters with improved electrical properties. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Indium incorporation into InGaN and InAlN layers grown by metalorganic vapor phase epitaxy

“…In our previous paper [13], we reported a smaller indium incorporation into the InGaN layers grown on misoriented substrates, as well as larger FWHM of PL peak for those samples, despite smaller indium content in the layers. CL studies showed higher indium incorporation on terraces than at steep stepbunched terrace edges.…”

“…The application of such misoriented substrate has an advantage of higher hole concentration [12] and better morphology, but lower indium incorporation [13].…”

Effect of substrate offcut on AlGaN/GaN HFET structures on bulk GaN substrates

“…3 However, very few reports on the effects of offcut of bulk GaN substrates on subsequent epitaxy exist in the literature, and these are primarily concerned with the growth of InGaN as compared to AlGaN. 4,5,6 This work aims to elucidate the effect of the surface offcut on the compositional and electrical performance of AlGaN/GaN heterostructures on bulk GaN substrates.…”

Lateral Control of Indium Content and Wavelength of III–Nitride Diode Lasers by Means of GaN Substrate Patterning

“…[6][7][8][9][10][11][12][13][14] All the experiments described in those references were performed using different homogeneous GaN substrates with different vicinal angles. In this work, we show that the different vicinal angles could be realized within one patterned substrate.…”