Verallgemeinerte Ferninfrarot-Ellipsometrie von Ladungsträger-Magnetfeld-Effekten in III-V Verbindungshalbleiter Schichtstrukturen

• Applicant: Professor Dr. Mathias Schubert
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2004 to 2007
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5418143

The electron and hole effective mass m* and mobility u, and their dependence an the carrier concentration N shall be accurately determined using magnetooptic ellipsometry for exemplary multinary alloy zincblende group-III-group-V semiconductors. Materials of technological importance and current scientific interest investigated in this proposal are AIGaInP, and boron or nitrogen diluted InGaAs alloys, respectively. They can be grown n- or p-type with sufficiently high values of N, and u, and with excellent crystal quality by metal-organic vaporphase-epitaxy. When brought into magnetic fields, the free carriers cause birefringence at far-infrared wavelengths providing access to N, m*, and ,u independently from each other. Tools for the determination of the complex-valued magnetooptic birefringence in semiconductor layer structures are lacking completely at present. We will (1) setup a new far-infrared magnetooptic ellipsometer capable of reaching B = ±6 Tesla, and T = 4K ... 293K at the sample, and (2) determine the free-carrier-induced magnetooptic birefringence of n- or p-type materials within semiconductor layer structures, as a function of the magnetic field strength and Sample temperature, by far-infrared magnetooptic generalized ellipsometry, and (3) determine m, p, N, exemplarily for n- and p-type AIGalnP, InGaNAs, and BInGaAs alloys, and subsequently evaluate the dispersion of the accessible valence and conduction bands in the vicinity of the I'-point, and elucidate optical carrier scattering mechanisms.

• DFG Programme: Research Grants