Growth of high crystal quality InN by ENABLE‐MBE

Abstract

AbstractIndium nitride is of interest as a small band gap material for hot carrier solar cells and for alloying of III‐Nitrides in conventional solar cells. Growth of photovoltaic device quality InN on cost effective sapphire wafers is challenging. Lattice mismatch between sapphire and indium nitride (∼25%) makes growth of epitaxial crystals with low crystalline imperfection problematic. InN films with promising XRD results were grown by MBE using a well‐aligned AlN buffer layer to grow InN on sapphire substrates. Crystal quality, analyzed by HRXRD, gives evidence that films of both AlN on sapphire and InN on AlN are almost fully relaxed by edge dislocations created on the interfaces with a rather low density of closed dislocation loops, created subsequently in the film volume of both epitaxial layers. These films exhibit threading dislocation densities of 3 x 107 cm‐2 and 2 × 108 cm‐2 for AlN and InN. Additional metrics quantifying film quality of AlN and InN characterized by XRD and TEM will be presented. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)