Photoluminescence studies of ZnSe starting materials and vapor grown bulk crystals

Su, Ching‐Hua; Feth, S.; Wang, Ling Jun; Lehoczky, S. L.

doi:10.1016/s0022-0248(01)00770-9

Cited by 17 publications

(12 citation statements)

References 37 publications

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“…The absorption edge is very sharp and is located at about 465 nm (Fig. 7), corresponding to that reported in the literature [63]. This is in good agreement with the energy band gap of 2.67 eV.…”

Section: Optical Studiessupporting

confidence: 90%

Quantum phenomena of ZnSe nanocrystals prepared by electron beam evaporation technique

Kaviyarasu¹

2016

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Substrate temperature dependent optical and structural properties of Zinc selenide (ZnSe) thin films were studied. Films were grown onto glass substrate by electron beam evaporation technique in high vacuum (10-6 Torr) at various temperatures in range of room temperature (RT) to 300 °C. Microstrain and dislocation density were also found to vary between 0.69×10 -3 , 1.12×10 -3 , 3.59×1010 cm -2 and 9.49×1010 cm -2 . The lattice parameter value 'a' for these films was calculated and found to increase from 5.577 Å to 5.652 Å respectively. Scanning electron micrographs (SEM) showed that clusters are composed of spherical and needle like nanocrystals distributed uniformly over the surface whose c-axis is parallel to the surface of the film. This confirmed the mixture comprised cubic and hexagonal phases. A comparison of atomic force microscopy (AFM) images showed that the grain size increased from about 139 nm for the RT deposited ZnSe film to about 39 nm for the ZnSe film deposited at 300 °C. The binding energy of 54.4 eV is similar to the values obtained for other selenides. The Auger parameter for zinc was calculated from the experimental binding energies of the zinc (2p 3/2 ) XPS line and the LMM Auger line the reference values are 1042.49 eV -1020.19 eV for zinc. All the films were characterized optically by UV-vis-NIR spectrophotometer in photon wavelength range (300 nm -2000 nm). The optical transmittance and reflectance were utilized to compute the absorption coefficient, refractive index and band gap energy of the films. The bandgap value of RT and 100 oC deposited ZnSe films are 2.88 eV and 2.78 eV, which are found to be blue shifted by about 0.08 -0.18 eV from the bandgap value of 2.70 eV for the standard bulk material.

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Section: Optical Studiessupporting

confidence: 90%

Quantum phenomena of ZnSe nanocrystals prepared by electron beam evaporation technique

Kaviyarasu¹

2016

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“…According to the results of Refs. [30,31] residual Al content in the silica tube [30] and the origin of Cl impurities can be located in an unintentionally handling of the tube with bare hands. The origin of the Cu contamination is more difficult to assess.…”

Section: Resultsmentioning

confidence: 99%

Photoluminescence Study of ZnSe Single Crystals Obtained by Solid Phase Recrystallization under Different Pressure Conditions. Effects of Thermal Treatment

Garca

Remn

Zubiaga

et al. 2002

phys. stat. sol. (a)

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ZnSe single crystals, obtained by the Solid Phase Recrystallization (SPR) method under three different pressure conditions, 10 and 5 atm of Se, and 2 atm of argon, have been investigated by means of photoluminescence (PL) and optical microscopy. Special attention has been paid to the surface state of the samples. Samples recrystallized under 10 atm of Se present the best rate between the PL response for the excitonic zone and the deep level one that shows a “clean” PL emission without significant peaks and/or bands. The presence of slip bands has been detected and analysed by means of optical microscopy and photoluminescence. In order to study the changes introduced by post growth thermal treatments, we have analysed the low temperature PL response on SPR samples after different thermal treatments. Striking changes have been detected in the PL response before and after the thermal treatment. The involved mechanisms have been studied.

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“…In [18] and [19] the peak at 2724 meV is also ascribed to the oxygen-related DAP transitions, and a wide maximum around 2530 meV is argued to be related to a complex containing oxygen. The last opinion is repeated in [20]. The two lines at 2787.7 meV and 2789.5 meV, observed for oxygen-containing ZnSe epilayer (shifted a little with respect to their bulk positions due to the strain) are ascribed to oxygen in [21], but there this impurity is treated as an isoelectronic trap exactly of the same kind, as oxygen in ZnTe [22].…”

Section: Role Of Oxygen In the Process Of Growthmentioning

confidence: 89%

“…1a was flat not only to 2000 meV, but down to 1600 meV, where it was measured with a little smaller sensitivity. According to [20], 4 ppm of oxygen manifest itself in the PL specrum. The density of dislocations, measured as the etch pit density for the ZnSe crystals, is approximately 2Â10 5 cm À2 .…”

Section: Role Of Oxygen In the Process Of Growthmentioning

confidence: 99%

Technology and Characterization of Single-Crystalline Substrates Made of ZnSe-Based Wide-Gap II-VI Semiconductor Compounds

Mycielski

Szadkowski

Kowalczyk

et al. 2002

phys. stat. sol. (b)

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Detrimental role of traces of oxygen in the growth process of the ZnSe-based wide-gap II-VI semiconductor crystals is emphasized. Adhesion, enhanced by the presence of oxygen, of the growing crystal to the walls of the quartz ampoule promotes generation of twinning and dislocations. The technology of the substrate-quality crystals, which ensures nearly complete removal of oxygen, is described. The results of characterization of the obtained large (25 mm diameter), twin-free single crystals of ZnSe, and substrate plates are presented.Introduction The II-VI semiconductor technology based on epitaxy (MBE, MOCVD) requires substrates, which have to be cut out of very high quality single crystals (at least 1 inch diameter), preferentially of the II-VI compound, as generally much better results can be achieved with homoepitaxy rather than with heteroepitaxy. It has been shown for example [1], that creation of a very bad interface accompanies the heteroepitaxial growth of ZnSe on a GaAs substrate. To avoid twinning, which plagues hightemperature crystallization, the methods of growth at temperatures lower than the melting point, like solid-phase recrystallization [2], chemical vapour transport and physical vapour transport (PVT) [3], are widely investigated and developed.We are using self-seeded PVT for the growth of ZnSe and Zn(Se,S) substrate crystals (1 inch diameter). Our high-quality crystals have been described e.g. in [4]. The poor reproducibility of the successful growth was the biggest remaining problem, and the growth of crystals with larger diameters appeared to be impossible. Now, the main reasons of the difficulties seem to be found. Beside not always perfect stoichiometry, it is residual oxygen.

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Photoluminescence studies of ZnSe starting materials and vapor grown bulk crystals

Cited by 17 publications

References 37 publications

Quantum phenomena of ZnSe nanocrystals prepared by electron beam evaporation technique

Quantum phenomena of ZnSe nanocrystals prepared by electron beam evaporation technique

Photoluminescence Study of ZnSe Single Crystals Obtained by Solid Phase Recrystallization under Different Pressure Conditions. Effects of Thermal Treatment

Technology and Characterization of Single-Crystalline Substrates Made of ZnSe-Based Wide-Gap II-VI Semiconductor Compounds

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