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Quantum dots for temperature sensing

Doskaliuk Natalia, Lukan Yuliana, Khalavka Yuriy

Scientiae Radices

2023

Vol. 2, Iss. 2

93--111

Quantum dots are three-dimensional nanoparticles of semiconductors with typical sizes ranging from 2 to 10 nm. Due to the quantum confinement effect the energy gap increase with the size decreasing resulting in size-depended and fine-tunable optical characteristics. Besides this, the energy structure of a quantum dot with a certain size is highly sensitive to environmental conditions. These specific properties open a wide range of applications starting from optical and optoelectronic devices and ending with biosensing and life science. Temperature is one of those parameters influencing strongly on the optical properties of semiconductor nanocrystals, which make them promising materials for temperature sensing, more often using a fluorescent response. Compared to the conventional organic dyes already applied in this field, quantum dots exhibit a set of advantages, such as high quantum yield and photostability, long fluorescence lifetime, higher Stokes shift, and ability to surface functionalization with targeted organic molecules aimed to provide them biocompatibility. In this review, we briefly discuss the properties of II-VI and assumingly less toxic I-III-VI quantum dots, mechanisms of temperature-induced fluorescence response, and the feasibility of their practical application in the field of thermal sensing.

Identification of the Volume and Surface Type Absorption by the Nondestructive Photoacoustic Method

Maliński M. A., Chrobak Ł. B.

Zeszyty Naukowe Wydziału Elektroniki i Informatyki Politechniki Koszalińskiej

2012

Nr 4

5--14

This paper presents experimental and theoretical amplitude and phase photoacoustic spectra of the mixed crystal ZnBeMgSe. The experimental photoacoustic spectra with the microphone detection were analyzed in a surface and volume absorption model. This paper proves that it is not possible to draw conclusions about the character of the absorption i.e. volume or surface only from the amplitude or phase photoacoustic spectra. It is possible to identify the character of the absorption only from the amplitude and phase photoacoustic spectra together.

W artykule przedstawiono eksperymentalne i teoretyczne fotoakustyczne widma amplitudowe i fazowe kryształu ZnBeMgSe. Eksperymentalne widma fotoakustyczne uzyskane przy zastosowaniu detekcji mikrofonowej zostały zinterpretowane w modelu absorpcji objętościowej i powierzchniowej. Artykuł dowodzi, że nie jest możliwe wyciągnięcie wniosków odnośnie optycznej absorpcji objętościowej i powierzchniowej tylko z charakteru fotoakustycznego widma amplitudowego lub fazowego. Możliwe jest to przy jednoczesnej interpretacji zarówno fotoakustycznego widma amplitudowego jak i fazowego.

Study of Zn1-xMgxSe and Zn1-xBexSe semiconducting crystals by Raman scattering

Szybowicz M., Kozielski M., Firszt F., Łęgowski S., Męczyńska H., Szatkowski J., Paszkowicz W.

Opto-Electronics Review

1999

Vol. 7, No. 2

103-106

Wide gap II-VI mixed crystals containing Mg and Be are recently studied extensively for their application in constructing blue-green laser diodes. This work deals with experimental study of optical modes in Zn1-xMgxSe and Zn1-xBexSe semiconductors using Raman scattering method. Measurements have been performed at room and liquid nitrogen temperatures for Zn1-xMgxSe crystals with Mg content in the range 0 < x < 0,34 and for Zn1-xBexSe with Be content in the range 0 < x 0,26. From polarised Raman spectra the longitudinal (LO) and the transverse (TO) optical mode, corresponding to ZnSe- and MgSe - like modes in Zn1-x MgxSe and to ZnSe- and BeSe - like modes in Zn1-xBexSe, were determined. These lattice vibrations can be described by the modified random element isodisplacement (MREI) model.