Regensburg 2004 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 9: Heterostrukturen I
HL 9.4: Vortrag
Montag, 8. März 2004, 16:00–16:15, H17
Piezo-electric fields in InGaAsP induced by spontaneous self-ordering — •S. Krämer1, G. H. Döhler1, S. Neumann2, W. Prost2, and T. J. Tegude2 — 1Institut für Technische Physik I, Universität Erlangen-Nürnberg, Erwin-Rommel-Str. 1, D-91058 Erlangen — 2Fachbereich Halbleitertechnik/Halbleitertechnologie, Universität Duisburg, Lotharstr. 55 LT, D-47048 Duisburg
InGaAsP grown by MOCVD under specific growth conditions form a monolayer superlattice along the [111]-0.5exB direction ("spontaneous self-orderingNo-dq). This superlattice can be formed by InP-GaAs or InAs-GaP. Because of the different bond lengths in these combinations the resulting two No-dqversionsNo-dq of InGaAsP would have varying distances between the alternating layers compared to unstrained bulk material. For InGaAsP, grown lattice matched on an InP-substrate, these different layer sequences lead to significant piezo-electric fields in the range of about 100 kV/cm. The existence of order-induced piezo-electric fields for ordered GaInP, lattice matched to GaAs, has been discussed controversially in the literature [1], [2], [3]. To investigate the occurrence, sign, and magnitude of piezo-electric fields in the InGaAsP-system, we embedded an InGaAsP - quantum well in an InP - pin and - nip structure, respectively. By observing the quantum confined Stark effect in the photocurrent signal in both structures we were able to determine the strength (and sign) of the piezo-electric field to about 130 kV/cm in ordering direction.
[1]: S. Froyen et al. APL 68, 2852 (1996)
[2]: P. Ernst et al. ICPS 23 World Scientific 1996
[3]: J. D. Perkins et al. JAP, 84 (1998)