Dislocation-independent mobility in lattice-mismatched epitaxy: application to GaN

• Published in: Solid state communications Vol. 117; no. 10; pp. 571 - 575
• Main Authors: Look, D.C., Stutz, C.E., Molnar, R.J., Saarinen, K., Liliental-Weber, Z.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.2001; Elsevier
• Subjects: A. Interfaces; B. Epitaxy; C. Dislocations; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Conductivity phenomena in semiconductors and insulators; Defects and impurities in crystals; microstructure; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in condensed matter; Electronic transport in interface structures; Exact sciences and technology; Iii-v semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions; Linear defects: dislocations, disclinations; Low-field transport and mobility; piezoresistance; Physics; Structure of solids and liquids; crystallography; 73.61.Ey; 61.72.Lk; C. Dislocations; B. Epitaxy; 73.40.Kp; A. Interfaces; Inorganic compounds; Semiconductor materials; Gallium nitrides; Scattering; Epitaxy; Binary compounds; Solid-solid interfaces; Experimental study; Dislocations; Mismatch lattice; Carrier mobility; Carrier density; Aluminium oxides
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/S0038-1098(01)00010-2

Lattice-mismatched epitaxy produces a high concentration of dislocations ( N dis) in the interface region, and this region is often highly conductive, due to donor ( N D) decoration of the dislocations. Here we show that a simple postulate, N D= α( N dis/ c), where c is the lattice constant and α a constant of order 1–2, predicts a nearly constant low-temperature mobility, independent of N dis. This prediction is experimentally verified in GaN grown on Al 2O 3, and is also applied to other mismatched systems.