Growth and Raman spectra of doped ZnO single crystals

Structural and optical properties of indium-doped highly conductive ZnO bulk crystals grown by the hydrothermal technique

“…Broad spectral features in the range of 500-600 cm -1 found in hydrothermal bulk crystals doped with other impurities, e.g. Mn [17] are not seen in the bulk In-doped crystal. Similarly, several other peaks which were found in epitaxial ZnO films doped with a number of different metals such as Sb, Ga, and Al [7,19] are not seen in our crystals.…”

“…The (0001) surface has a number of growth hillocks arising from the indium contamination. Otherwise, the surface of new growth area is smooth and of high quality despite there are growth zones overlapped on the {0001} faces, observed on the cross-section (11)(12)(13)(14)(15)(16)(17)(18)(19)(20), as shown in Fig.1 The a-and c-parameters of pure hexagonal ZnO are 3.2498 Å and 5.2066 Å, respectively. X-ray diffraction on the doped crystal showed that the a-parameter is 3.243Å, which is 0.2% lower than the pure ZnO value [13], and the c-parameter is 5.210 Å, greater than the undoped lattice constant.…”

“…In short, Li from the mineralizer LiOH is known to incorporate into Zn sites to shrink the lattice [16], while In incorporates into ZnO to expand the lattice [17]. The overgrowth completely encases the seed crystal.…”

“…The A 1 and E 1 modes are polar and thus split into transverse (TO) and longitudinal (LO) components [17]. Unpolarized and polarized Raman spectra were measured on (0001), (000-1) natural faces and (11-20) cross-section of In:ZnO single crystals in the following backscattering geometries: ( ) ̅ , (− −) ̅ (unpolarized), ̅ ( ) , ̅ (− −) (unpolarized), and (− −) ̅ (unpolarized) as shown in Fig.4.…”

Growth Measures to Achieve Bulk Single Crystals of Transparent Semiconducting and Conducting Oxides

“…The most successful technique for growing large ZnO single crystals of high quality is [49][50][51][52][53][97][98][99][100][101][102][103]. This method, shown schematically in Figure 6.7(a), is conducted in autoclaves made of steel with a platinum, silver, or titanium-alloy liner to isolate the growth environment from the autoclave containing an aqua alkaline solution of KOH and NaOH (mineralizer).…”