Novel nano-faceting structures grown on patterned vicinal (110) GaAs substrates by metal-organic vapor phase epitaxy (MOVPE)

We describe periodic nano-faceting structures formed naturally on patterned vicinal (110) GaAs grown by metal-organic vapor phase epitaxy (MOVPE). Periodic trenches are formed along the [1-10] direction on initial surfaces with pattern periods of 2 mum. 1 mum, 800 nm, and 600 nm. Periodic nano-faceting structures consisting of (110) and (111)B surfaces are clearly formed on the GaAs grown surfaces, and the periods are almost exactly equal to the pattern periods. The growth modes are observed from cross-sectional scanning electron microscope (SEM) images of GaAs/AlGaAs multilayer growth. The growth rate of the (111)B sidewall facets is higher than that of the (110) terraces, which indicates that quantum wire (QWR) structures can be formed naturally at step edges. Quantum well (QW) structures of GaAs/In0.18Ga0.82As/GaAs are also grown on patterned vicinal substrates. A photoluminescence (PL) spectrum at 4 K shows two sharp emission peaks from QWs on the (111)B sidewall facets at a lower energy and on the (110) terraces at a higher energy. These results suggest that it is possible to fabricate QWR arrays with high uniformity on (111)B sidewall facets.