(PbWO 4 ), an important inorganic scintillator, was also hydrothermally synthesized
[4]. By using LiOH and Nb 2 O 5 as the reactants, 40–100 nm flake-like LiNbO 3
nanocrystallites [5] were prepared.
To avoid the toxicity of thallium oxides in high temperature solid state reactions,
a hydrothermal reaction containing Tl(NO 3 ) 3 , BaO, CuO and CaCO 3 with H 2 O 2 at
160
C was designed and a Tl-based superconductor, Tl 2 O 3 aCaOaBaCu 3 O 4 , with
T c onset near 95 K and zero resistance at 65 K has been prepared [6]. X-ray diffraction (XRD) studies showed that the products consisted of at least two superconducting phases (2201 and 2212). Figure 7.1 shows the XRD pattern and the
R–T curve of the Tl-based superconductor. As a mixed valent magnetite, cubic
perovskite structure La 0:5 Ba 0:5 MnO 3 single-crystal nanowires with [110] orientation were grown hydrothermally at 270
C [7]. They show an enhanced magnetoresistance effect as compared to the bulk crystals.
Fe-passivated porous silicon (PS) with non-degrading photoluminescence (PL)
was prepared by treating P/P
þ -type, boron-doped single crystal (111) Si wafers at
140
C in an aqueous solution with 40 wt% HF and 0.3 M Fe(NO 3 ) 3 (volume
ratio, 7/6) [8, 9]. As shown in Figure 7.2, for freshly prepared samples, the PL peak
intensity is 2–2.5 times stronger than that of ordinary PS. Furthermore, unlike
Fig. 7.1. The XRD pattern (A) and the R–T curve (B) of the Tlbased superconductor prepared by the hydrothermal method.
7.1 Introduction 171
[4]. By using LiOH and Nb 2 O 5 as the reactants, 40–100 nm flake-like LiNbO 3
nanocrystallites [5] were prepared.
To avoid the toxicity of thallium oxides in high temperature solid state reactions,
a hydrothermal reaction containing Tl(NO 3 ) 3 , BaO, CuO and CaCO 3 with H 2 O 2 at
160
C was designed and a Tl-based superconductor, Tl 2 O 3 aCaOaBaCu 3 O 4 , with
T c onset near 95 K and zero resistance at 65 K has been prepared [6]. X-ray diffraction (XRD) studies showed that the products consisted of at least two superconducting phases (2201 and 2212). Figure 7.1 shows the XRD pattern and the
R–T curve of the Tl-based superconductor. As a mixed valent magnetite, cubic
perovskite structure La 0:5 Ba 0:5 MnO 3 single-crystal nanowires with [110] orientation were grown hydrothermally at 270
C [7]. They show an enhanced magnetoresistance effect as compared to the bulk crystals.
Fe-passivated porous silicon (PS) with non-degrading photoluminescence (PL)
was prepared by treating P/P
þ -type, boron-doped single crystal (111) Si wafers at
140
C in an aqueous solution with 40 wt% HF and 0.3 M Fe(NO 3 ) 3 (volume
ratio, 7/6) [8, 9]. As shown in Figure 7.2, for freshly prepared samples, the PL peak
intensity is 2–2.5 times stronger than that of ordinary PS. Furthermore, unlike
Fig. 7.1. The XRD pattern (A) and the R–T curve (B) of the Tlbased superconductor prepared by the hydrothermal method.
7.1 Introduction 171