The optical properties of multi-layer InAs/InP quantum wires (QWRs) with two different spacer thicknesses have been investigated by means of room temperature surface photovoltage (SPV) and photoluminescence (PL) spectroscopies, combined with empirical tight binding electronic structure calculations and structural data. The SPV and PL spectra reveal several features, which energy positions are in good agreement. They have been ascribed to excitonic transitions, which take place in the QWR families with heights differing by an integer number of monolayers. Comparing the experimental results with the theoretical ones, we have estimated the QWR family heights and the average atomic concentration of phosphorus in the QWRs. From the simultaneous analysis of the SPV amplitude and phase spectra, based on our vector model for SPV signal representation, a deeper understanding of the SPV results and of the mechanisms of carrier separation in the sample is obtained.

This work was supported by the Sofia University research fund (contract 149/2010), Ministry of Education and Science of Spain (MAT2009-10350, FEDER) and the Alexander von Humboldt Foundation. The authors would like to thank assoc. prof. Germanova for the critical reading and fruitful discussions.

Trabajo presentado en el 16 ISCMP: Progress in Solid State and Molecular Electronics, Ionics and Photonics, celebrado en Varna (Bulgaria), del 29 de agosto al 3 de septiembre de 2010

Peer reviewed