Near-field microscopy of waveguide architectures of InGaN/GaN diode lasers

Abstract

Waveguide (WG) architectures of 420 nm emitting InGaN/GaN diode lasers are analyzed by photoluminescence and photocurrent spectroscopy using a nearfield scanning optical microscope that scans along their front facets. The components of the 'optical active cavity', quantum wells, WGs, and cladding layers are individually inspected with a spatial resolution of ∼100 nm. Separate analysis of the p-and n-sections of the WG was achieved, and reveals defect levels in the p-part. Moreover, it is demonstrated that the homogeneity of the n-WG section directly affects the quantum wells that are grown on top of this layer. Substantially increased carrier capture efficiencies into InGaN/GaN-WGs compared to GaN-WGs are demonstrated.

Optical Characterization of InGaN Quantum Structures at the Nanoscale

“…Similarly in 2016, S. Friede et al analyzed the architectures of 420 nm emitting InGaN/GaN diode lasers by photoluminescence and photocurrent spectroscopy using a nearfield scanning optical microscope. [39] They were able to individually inspect the components of the "optical active cavity", such as quantum wells, waveguides, and cladding layers. Their study revealed defect levels in the p-part of the waveguide and suggested that the homogeneity of the n-waveguide section directly affects the quantum wells grown on top of this layer.…”