Temperature dependence of the absorption spectra in CdTe-doped glasses

We present absorption spectra as a function of temperature for CdTe quantum dots in doped glasses. We calculate the absorption spectra considering the transition energies from a spherical model. We consider also the inhomogeneous broadening due to the quantum-dot size distribution and the homogeneous broadening, due mainly to electron-phonon interactions. The samples grown with a two-step heat treatment present very thin size distributions, with a standard deviation of 5.8%, which is comparable to the best CdSe samples in the literature. Also, the results show that the homogeneous width increases as the quantum-dot size decreases, indicating an enhancement of the electron-phonon interaction for small dots.

[1]  K. I. Kang,et al.  OPTICAL PROPERTIES OF CdTe AND CdS QUANTUM DOTS IN GLASS , 1992 .

[2]  Norris,et al.  Observation of the "Dark exciton" in CdSe quantum dots. , 1995, Physical review letters.

[3]  A. Alivisatos.  Semiconductor Clusters, Nanocrystals, and Quantum Dots , 1996, Science.

[4]  Norris,et al.  Measurement of the size dependent hole spectrum in CdSe quantum dots. , 1994, Physical review letters.

[5]  L. C. Barbosa,et al.  Cdte Quantum Dots By Melt Heat Treatment In Borosilicate Glasses , 1997 .

[6]  Norris,et al.  Measurement and assignment of the size-dependent optical spectrum in CdSe quantum dots. , 1996, Physical review. B, Condensed matter.

[7]  Murray,et al.  Fluorescence-line narrowing in CdSe quantum dots: Surface localization of the photogenerated exciton. , 1994, Physical review. B, Condensed matter.

[8]  P. Lefebvre,et al.  Quantum confinement effects of CdS nanocrystals in a sodium borosilicate glass prepared by the sol‐gel process , 1995 .

[9]  C. César,et al.  Ultrafast processes in semiconductor doped glasses , 1997 .

[10]  T. Koyama,et al.  Nonlinear optical properties of CdTe microcrystallites doped glasses fabricated by laser evaporation , 1995, Technical Digest. CLEO/Pacific Rim'95. The Pacific Rim Conference on Lasers and Electro-Optics.

[11]  Norris,et al.  Size dependence of exciton fine structure in CdSe quantum dots. , 1996, Physical review. B, Condensed matter.

[12]  Richard,et al.  Effects of finite spin-orbit splitting on optical properties of spherical semiconductor quantum dots. , 1996, Physical review. B, Condensed matter.

[13]  A. Herhold,et al.  Comparison of quantum confinement effects on the electronic absorption spectra of direct and indirect gap semiconductor nanocrystals. , 1994, Physical review letters.

[14]  Richard,et al.  Measurement of the optical band gap and crystal-field splitting in wurtzite CdTe. , 1996, Physical review. B, Condensed matter.

[15]  M. Stroscio,et al.  Size dependence of the thermal broadening of the exciton linewidth in GaAs/Ga0.7Al0.3As single quantum wells , 1992 .

[16]  Norris,et al.  Photoluminescence Spectroscopy of Single CdSe Nanocrystallite Quantum Dots. , 1996, Physical review letters.

[17]  Sercel,et al.  Application of a total-angular-momentum basis to quantum-dot band structure. , 1990, Physical review letters.

[18]  Alivisatos,et al.  Quantum size dependence of femtosecond electronic dephasing and vibrational dynamics in CdSe nanocrystals. , 1994, Physical review. B, Condensed matter.

[19]  S. Tolbert,et al.  Size Dependence of a First Order Solid-Solid Phase Transition: The Wurtzite to Rock Salt Transformation in CdSe Nanocrystals , 1994, Science.

[20]  C. César,et al.  PROBING OF THE QUANTUM DOT SIZE DISTRIBUTION IN CDTE-DOPED GLASSES BY PHOTOLUMINESCENCE EXCITATION SPECTROSCOPY , 1995 .

[21]  Y. Masumoto,et al.  SIZE-DEPENDENT ENERGY LEVELS OF CDTE QUANTUM DOTS , 1997 .

[22]  A. Alivisatos,et al.  Light-emitting diodes made from cadmium selenide nanocrystals and a semiconducting polymer , 1994, Nature.

[23]  Klingshirn,et al.  Homogeneous linewidth of confined electron-hole-pair states in II-VI quantum dots. , 1993, Physical review. B, Condensed matter.

[24]  C. César,et al.  Size effects on the phonon spectra of quantum dots in CdTe‐doped glasses , 1996 .

[25]  A. Ekimov.  Growth and optical properties of semiconductor nanocrystals in a glass matrix , 1996 .

[26]  Sercel,et al.  Analytical formalism for determining quantum-wire and quantum-dot band structure in the multiband envelope-function approximation. , 1990, Physical review. B, Condensed matter.