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HL: Fachverband Halbleiterphysik

HL 98: Nitrides: Bulk material, films, surfaces and quantum wells

HL 98.6: Vortrag

Freitag, 20. März 2015, 11:00–11:15, EW 201

Growth and characterization of InN on Si (111) by molecular beam epitaxy — •Saskia Weiszer, Andreas Zeidler, Fabian Schuster, and Martin Stutzmann — Walter Schottky Institut and Physics Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany

Multi-junction solar cells have received wide attention as the energy conversion efficiency can be increased significantly compared to single-junction solar cells. Theoretical considerations show that an InGaN/Si tandem solar cell could be an optimal implementation of a double-junction solar cell, as two different wavelength regions of the broad solar spectrum can be utilized by each junction connected via a resonant tunnel junction which is expected to form at an indium content of 46 %. As a first step towards such an InGaN/Si tandem solar cell, the growth of high quality InN directly on Si (111) substrates by molecular beam epitaxy (MBE) has been investigated. First attempts of growing InN as a homogeneous thin film suffered from an insufficient quality. The obtained layer-like structures showed high surface roughness in atomic force microscope and various epitaxial orientations measured by high resolution X-ray diffraction. A possible alternative to layer growth is the growth of nanowires to reduce structural defects, since the lattice mismatch induced strain can relax through the nanowire sidewalls. By a varying the applied growth parameters, namely substrate temperature and III/V-ratio, the InN nanowire growth has been optimized and recent results will be presented.