Polarization anisotropy in room temperature contactless electroreflectance spectrum of self-organized lateral compositional superlattices

Ghosh, Sandip; Arora, B. M.; Kim, S.-J.; Asahi, H.

doi:10.1006/spmi.1998.0577

Cited by 3 publications

(3 citation statements)

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“…Pearah et al [5] explained the polarization dependence of the PL originating in the LS on the basis of strains in the Ga/In rich regions. Recently Ghosh et al [6] have suggested another possible explanation for the polarization anisotropy of the CER feature A1 that is associated with the LCM in the sample which briefly is as follows. At the valence band edge of the III-V semiconductors with zinc blende structure, the cell periodic parts of the heavy hole (hh) and the light hole (lh) wavefunctions can be described using the p x , p y and p z atomic orbitals.…”

Section: Origins Of Cer and Pl Signalsmentioning

confidence: 99%

“…A large shift of the photoluminescence (PL) peak position to lower energy has been observed in these samples and has been explained by suggesting that LCM leads to the formation of a lateral superlattice (LS) and the PL signal arises from carrier recombination in the In rich low energy well regions of the LS. Strongly polarization sensitive optical properties have also been reported and put forth as evidence for LCM [4][5][6]. A theoretical model which considers the Ga and the In rich regions as coherently strained random Ga x In 1−x P alloys has been used to describe the electronic band structure of these materials.…”

Section: Introductionmentioning

confidence: 99%

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Spectroscopic study of Ga-In-P based self-organized lateral superlattices

Ghosh¹,

Arora²,

Kim³

et al. 1999

Semicond. Sci. Technol.

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This paper reports polarization and temperature dependent contactless electroreflectance (CER) and photoluminescence (PL) study of strain compensated short period (GaP) 2 (InP) 2 superlattices on GaAs(001) substrates which show self-organized lateral composition modulation (LCM) in the form of alternate In/Ga rich regions along the [110] direction in the (001) plane. The LCM related PL peak position is at a lower energy as compared to the corresponding feature in the CER spectrum and the difference is found to be the same as the activation energy for thermal quenching of the PL signal. These results have been explained by suggesting that the PL signal arises mainly from recombination of carriers localized at potential fluctuations (In rich regions with excessively high In concentration) within the lateral superlattice (LS) structure that is formed due to the LCM while the CER feature arises from transitions between the minibands of the average LS structure. The PL signal is quenched due to thermal excitation of the carriers from these excessively In rich regions into the minibands. The LS band gap energy is accurately determined and its implication for the random alloy model used to describe the electronic band structure of such systems is discussed. The temperature dependences of critical point energies have also been measured and analysed.

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Section: Origins Of Cer and Pl Signalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spectroscopic study of Ga-In-P based self-organized lateral superlattices

Ghosh¹,

Arora²,

Kim³

et al. 1999

Semicond. Sci. Technol.

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“…4 Evidence for this composition modulation was obtained from transmission electron microscope ͑TEM͒ pictures, energy dispersive x-ray analysis ͑EDX͒ and polarization dependent spectroscopic measurements. 5,6 It has been proposed that the process leading to this composition modulation is initiated by strongly anisotropic diffusion of the group III atoms on the GaAs surface and thereafter is sustained by strain induced nucleation of excess adatoms. 7 Use of these self-organized structures as building blocks to fabricate semiconductor quantum wire lasers has been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic study of self-organized quantum dot like structures in Ga–In–P superlattices on (311) GaAs

Ghosh

Arora

Kim

et al. 1999

Journal of Applied Physics

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We report temperature dependent photoluminescence, contactless electroreflectance and photoluminescence excitation study of ͑GaP͒ 2 ͑InP͒ 2.5 strained short period superlattices sandwiched between Ga x In 1Ϫx P alloy layers grown on GaAs ͑311͒A substrates. Transmission electron microscope pictures of these samples reveal the presence of self-organized In rich globular structures with Ga rich surroundings in the superlattice planes. The variation of the peak position of the photoluminescence band with decreasing temperature has an anomalous dip. We show that this is not due to an anomalous change in the band gap with temperature but is due to the interplay between two luminescence pathways associated with two phases, one which has the original ͑GaP͒ 2 ͑InP͒ 2.5 superlattice and the other being the self-organized composition modulated In rich regions within the superlattice layers. We also present spectroscopic results which indicate quantum dot like nature of the self-organized In rich structures in these samples.

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