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Room temperature characterisation of InGaAlAs quantum well laser structures using electro‐modulated reflectance and surface photovoltage spectroscopy

2009; Wiley; Volume: 206; Issue: 5 Linguagem: Inglês

10.1002/pssa.200881407

1862-6319

Natasha E. Fox, T. K. Sharma, Stephen J. Sweeney, T. J. C. Hosea,

Photonic and Optical Devices

Abstract In this study, two tri‐metal quaternary InGaAlAs quantum well (QW) laser structures grown on InP are compared to a conventional InGaAsP QW structure, also grown on InP, all designed to lase at 1.55 μm. Several spectroscopic methods are used to study the samples including surface photo‐voltage (SPV) and electro‐modulated reflectance (ER). In the tri‐metal samples the ground‐ and two excited‐state QW transitions are detectable in both types of spectroscopy. The SPV and ER give results in agreement to within a few meV of each other. By comparing the position of the measured QW transitions with those predicted theoretically, the conduction band offsets of the tri‐metal samples can be determined and compared to that in the InGaAsP sample. It is found that the tri‐metal samples have a much larger conduction band offset of ∼66% compared to the ∼40% in the InGaAsP sample. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)