MESOSCOPIC STEP ARRAYS BY PERIODIC STEP BUNCHING ON HIGH-INDEX GAAS-SURFACES

We observe the direct formation of mesoscopic surface corrugations on high-index GaAs substrates during growth by MBE. The accumulation of microscopic steps on GaAs (210) to form one-dimensional step arrays with a 230 angstrom lateral periodicity is monitored by RHEED. The high uniformity of these mesoscopic step arrays is confirmed by atomic force microscopy. The length scale of the lateral periodicity of 230 angstrom is comparable to the exciton Bohr radius of GaAs and it has thus pronounced influence on the electronic properties of GaAs/AlAs multilayer structures and AlGaAs/GaAs modulation doped n-type heterostructures. The enhanced integrated luminescence intensity and the anisotropy of the conductivity reveal the effective reduction of the lateral diffusion of carriers in these structures, highlighting their potential for advanced optoelectronic devices.