THE OBSERVATION OF THE MAGNETIC PHONON MODE IN MODULATION DOPED DILUTE Cd1-xMnxTe/Cd1-yMgyTe QUANTUM WELL STRUCTURE

The CdMnTe/CdMgTe quantum wells have been a focus of interests for its novel magnetic and transport properties and applications in spintronics. We have carried out a systematic study over a series of CdMnTe quantum wells with a range of Mn concentration (0%–3.9%) and modulation doping. Far-infrared transmission spectra have revealed several new infrared-active modes which are both magnetic-field and Mn -concentration dependent. The absorption mode near 125cm-1 (B1) is possibly resulted from the magnetic-order-dependent phonon mode due to an ion-position dependent spin Hamiltonian, while the other two (M1 & M2) may be related to the CdTe optical phonon modes.

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Study of Highly Strained Single InAs−In0.53Ga0.47As Quantum Wells from Phonon Modes by Raman Scattering

MRS Proceedings ◽

10.1557/proc-379-351 ◽

1995 ◽

Vol 379 ◽

Author(s):

L. G. Quagliano ◽

D. Orani ◽

A. Ricci ◽

M. G. Simeone ◽

M. R. Bruni

Keyword(s):

Raman Spectroscopy ◽

Quantum Wells ◽

Molecular Beam ◽

Phonon Mode ◽

Phonon Modes ◽

Long Wavelength ◽

Raman Study ◽

Highly Strained ◽

Inp Substrates

ABSTRACTWe report Raman study of highly strained single InAs−In0.53Ga0.47As quantum wells grown by molecular beam epitaxy (MBE) on InP substrates with the well thickness between 4 and 15 monolayers. We have used Raman spectroscopy to characterize quality, disorder and strain of these structures which are of considerable interest for long wavelength optical communications.In the Raman spectra we have observed an intense narrow line corresponding to the GaAslike LO mode of In0.53Ga0.47As cap layer and a narrow peak due to the LO phonon mode of the InAs layer. These dominant and sharp features characterize the high homogeneity of our samples. In addition to these features we have observed the appearance of distinct peaks with the increase of the InAs layer thickness. In our opinion the presence of these modes is indicative of a slight deterioration of the structural perfection of the sample with the increase of the well thickness. Our investigation shows the ability of Raman spectroscopy to describe these systems and the good quality of our structures.

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Far Infrared Spectroscopy of In0.53Ga0.47As Quantum Wells on InP(100)

MRS Proceedings ◽

10.1557/proc-744-m9.3 ◽

2002 ◽

Vol 744 ◽

Author(s):

N. L. Rowell ◽

D. J. Lockwood ◽

P. J. Poole ◽

G. Yu

Keyword(s):

Quantum Wells ◽

Far Infrared ◽

Interface Layer ◽

Scanning Tunneling ◽

Multiple Quantum ◽

Chemical Beam Epitaxy ◽

Phonon Confinement ◽

Phonon Modes ◽

Cross Sectional ◽

Interface Layers

ABSTRACTPolarized far infrared reflectance was measured at oblique incidence for In0.53Ga0.47As / InP multiple quantum wells grown by chemical beam epitaxy on InP(100) wafers. Both the well thickness (0.25 - 20 nm) and number of periods (10 - 40) were varied. The reflectance spectra contained sharp Berreman modes at the frequencies of the transverse (TO) and longitudinal (LO) optical phonons. The contributions of the individual phonons were resolved with the model fits. Interface layer phonon modes were observed with intensity increasing with number of wells. The interface layers were 0.6 nm thick and of different composition to adjoining wells consistent with cross-sectional scanning tunneling microscope results on the same samples. The variation due to phonon confinement of the InAs- and GaAs-like LO and TO phonon frequencies was obtained.

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