Temperature dependence of nanostructure in PbSe–ZnSe composite thin film

Abstract

The nanostructure of PbSe-ZnSe composite thin films prepared by the hot-wall deposition (HWD) method was investigated using small-angle x-ray (SAXS) scattering. The SAXS profiles indicate the formation of two kinds of nanoparticles: large nanoparticles that vanish and small particles that increase in size with increasing temperature. At high substrate temperatures, the volume fraction of all the nanoparticles estimated from SAXS is consistent with that of PbSe obtained by chemical analysis. This shows that PbSe forms nanoparticles at high substrate temperatures. On the other hand, the same analysis for the volume fraction at low substrate temperatures reveals that the chemical composition of the nanoparticles differs from PbSe. Pb nanoparticles are probably formed at low substrate temperatures and disappear with increasing substrate temperature.

One-step synthesis of composite thin film with ZnSe and PbTeSe ternary solid solution

“…The observed nanocrystal is thus found to be the ternary solid solution NaCl-I. It should be noted that the PbTe 1-x Se x thus observed crystallizes even at 274 K, while the XRD peak of PbSe in the PbSe-ZnSe composite thin films is weak even at the relatively high temperature of 403 K [24]. In contrast, PbTe crystallizes even at 274 K in PbTe-ZnTe composite thin films in our preliminary experiment.…”

Phase transformation from PbS to PbSe:S in hot-wall deposition of nanocomposite thin film with evaporation sources of PbS and ZnSe

“…6b). From direct observation using HAADF-STEM (not shown), PbSe crystallizes even at relatively low temperature of 280 K. The simple composite of selenide (i.e., PbSe-ZnSe) provided amorphous structure in PbSe at the temperature range [19]. Therefore, the low temperature stability in PbSe NCs suggests a slight inclusion of S, well corresponding to the EELS line scan analysis result (Fig.…”

“…Hence, lead and zinc chalcogenides, whose vapor pressure are similar and a relatively large, are useful for simultaneous evaporation. Following the material designs, the simple composites using evaporation sources of selenides (i.e., PbSe and ZnSe) and tellurides (i.e., PbTe and ZnTe) provided a characteristic of phase separation at heterointerface between PbSe NCs and ZnSe matrix or PbTe NCs and ZnTe matrix [17][18][19].…”

Preparation and low temperature stability of PbTe nanocrystals embedded in ZnTe matrix by hot-wall deposition

“…The dotted line indicates the peak position of standard PbTe and ZnTe. The diffraction peaks in PbTe with NaCl structure and ZnTe with zincblende structure are clearly observed at 274 K. Hence, the composite film with PbTe nanocrystals embedded in ZnTe matrix is crystallized even at a relatively low temperature of 274 K. In our previous study, the XRD peak of PbSe in the PbSe-ZnSe composite thin films is weak even at the relatively high temperature of 403 K [13]. Furthermore, nanoscale PbTeSe ternary solid solution crystallizes at a substrate temperature of 274 K in a composite film with ZnSe matrix [12].…”

“…Evaporation sources of PbTe and ZnSe produce a nanocomposite containing ZnSe and nanocrystalline PbSe with slight inclusion of Te (PbSe:Te), transforming from PbTe (evaporation source) to PbSe:Te (film production) [12]. Different evaporation sources (PbSe or PbTe), therefore, provide similar nanocrystalline PbSe, but the XRD peaks of pure PbSe nanocrystals are weak even at a relatively high substrate temperature of 403 K [13], whereas nanoscale PbSe:Te crystallizes even at 274 K [12]. These results suggest that slight inclusion of Te in PbSe nanocrystal stabilizes the crystalline phase.…”