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Antiphase domains are seen in single crystal gamma lithium aluminate (γ-LiAlO2) with 16.7 nm periodicity in the <110> direction. Alternate domains have a 12 [001] shift. Beta phase lithium aluminate (β-LiAlO2) is seen to form on the surface of the as-received wafers with an epitaxial strain limited relationship with the bulk γ phase. The orthorhombic β phase aligns with the a and b axes (0.528 and 0.630 nm) matching with the tetragonal γ phase’s a and c axes (0.5168 and 0.6268 nm). The γ and β phases are seen to have different etch rates. The β phase converts back to the γ phase above 450 °C. [ABSTRACT FROM AUTHOR]

Photoconduction (PC) properties in the ZnO films with the (110) nonpolar surface (a-plane) epitaxially grown by chemical vapor deposition on the LiGaO2 (010) substrates with low lattice mismatches (4.0% along the c-axis and 3.8% along the m-axis) have been studied. The structural and optical qualities of the epitaxial films have been characterized using theta-two theta and phi scans, X-ray diffraction, rocking curve, and photoluminescence measurements. The nonpolar ZnO film exhibits a near visible-blind ultraviolet photoresponse. The optimal photocurrent to dark current ratio (i.e., sensitivity) can reach 13360%. The responsivity of the a-plane ZnO photoconductor-type detector can also reach 1%7 AW-1, which is two to four orders of magnitude higher than those of the m-plane, a-plane, and r-plane photodiodes based on ZnO/ZnMgO quantum wells. The normalized gain at 2.%9 cm2V-1%, of the nonpolar film is also comparable with the optimal recorded value of the ZnO nanowires. In addition, the PC mechanism has also been investigated by the power-dependent and time-resolved photoconductivity measurements. The power-sensitive responsivity can be attributed to the effect of light intensity on carrier lifetime and quantum efficiency. The photovoltaic effect of the surface depletion region is inferred to be the reason resulting in the anomalous powerdependent quantum efficiency. [ABSTRACT FROM AUTHOR]