Bandstrukturuntersuchungen an Ga(In)NAs-basierten Halbleiter-Heterostrukturen mittels Modulations-und magnetooptischer Spektroskopie (English shop)

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Band structure investigations of Ga(In)NAs-based semiconductor heterostructures using modulation and magneto-optical spectroscopy

It is common to transmit data by using optical fibers. In this application area the material system GaInNAs attained more and more importance recently. One can fabricate optical devices which emit light in the near infrared (e.g. at 1.3µm). In this region common optical fibers have an attenuation minimum.
The band structure of nitrogen-based semiconductor materials is quite unusual and can be described by the so-called band anticrossing (BAC) model.
This work is about the effects on characteristic quantities which describe the band structure (EN, CMN), when different parameters are varied.
Using modulation spectroscopy on GaAsN bulk samples in the temperature region from 5-300 K the temperature dependence of EN, and for the first time CMN, is investigated. Measurements of the electronic states in GaInNAs/GaAs quantum wells with different indium concentration result in a decreasing value of CMN with increasing indium content. From samples with different composition the band offsets of the valence and conduction band could be extracted. Magneto-optical measurements (0 – 14 T) reveal information about localization effects on the charge carriers in the valence- and conduction band as well as the corresponding effective masses.