Hexagonal InN/sapphire heterostructures: interplay of interface and layer properties

Formation of an AlInN interface transition layer in plasma-assisted molecul ar beam epitaxy (PA MBE) of InN/Al2O3 (0001) structure has been found by hi gh-resolution X-ray diffraction (XRD), transmission electron microscopy (TE M), secondary ion mass-spectroscopy (SIMS) and optical transmission techniq ues. Having a thickness of below 100 nm, an Al content of similar to 0.3 an d rather sharp interfaces, the interlayer improves the quality of the main InN film, allowing its high-temperature growth without In droplet formation . XRD Theta-rocking curves width of 350 are sec, Hall mobility of 600 cm(2) /V s (300 K) at electron concentration of around 10(20) cm(-3) have been ac hieved for the best InN epilayer. Employed initial growth stage affects sig nificantly the quality of both the AlInN interface layer and the InN layer. (C) 2000 Elsevier Science B.V. All rights reserved.