MOMBE selective infill growth of InP/GaInAs for quantum dot formation

Quantum dots based on InP/GaInAs quantum wells were realised using epitaxial infill regrowth into a hole array formed in InP by means of e-beam lithography and reactive ion etching. Metal organic molecular beam epitaxy has been applied for selective infill growth. The growth procedure has been elaborated such that the vertical growth rate in predefined holes agrees with coherent growth and edge effects are minimised. Quantum dots formed in holes with a diameter ranging from 60 nm down to 30 nm in combination with a periodicity of 100 nm were studied. The achievement of quantum dots was evidenced by a blue shift of light emission with decreasing the geometrical quantum dot diameter, in qualitative agreement with calculations. Quantitative discrepancies were found because the effective lateral diameter of the quantum dots proved to be smaller than the geometrical value of the etched holes, caused by the lateral growth of the lower InP barrier.