Epitaxial growth of non-polar m-plane ZnO thin films by pulsed laser deposition

Strain Relaxation, Defects and Cathodoluminescence of m-Plane ZnO and Zn0.8Mg0.2O Epilayers Grown on γ-LiAlO2Substrate

“…21 The minimum FWHM value of ZMO is similar to that for an m-plane GaN epilayer of a similar thickness grown on LAO by metal organic vapor phase epitaxy but the latter possessed a higher FWHM anisotropy (∼3000 arcsec). 22 It is worth emphasizing that the FWHM values of both samples are low compared to the m-plane and a-plane ZnO grown on sapphire substrates, [3][4][5][6] especially for the ZMO one, though they are still about one order of magnitude higher than those of the homoepitaxial films reported recently. 8,9 Figs.…”

“…It is worth noting that, in addition to generating the misfit dislocations of b = 1 3 [1210], the plastic relaxation can also be accomplished 24 The slips result in a slight mosaic tilting with respect to the [0001] ZMO axis. Accordingly, the broadening of the (1010) ZMO reciprocal spot in the direction perpendicular to [0001] ZMO might be a result of the anisotropic tilting.…”

“…The growth of a-plane (i.e., (1120)) ZnO epilayers on (1102) sapphire is more successful than the m-plane epitaxy on the (1010) one, which may be attributed to the lower lattice misfits of the former. [3][4][5] However, the a-plane ZnO epilayers still suffer from high densities of threading dislocations (∼10 10 cm −2 ) and basal stacking faults (∼10 5 cm −1 ). 6,7 The finding reveals a crucial need for low lattice-misfit substrates for epitaxy of nonpolar ZnO.…”

Epitaxial growth of nonpolar m-plane ZnO epilayers and ZnO/Zn0.55Mg0.45O multiple quantum wells on a LiGaO2 (100) substrate

“…The direction having a high FWHM value seems to coincide with the stripe direction, which has been pointed out by Han et al 40 It is also worth noting that the FWHM values of both samples are low compared to the m-plane and a-plane ZnO epilayers grown on sapphire and LiAlO 2 substrates. 15,16,38 However, the FWHM of the (10 11) rocking curve for the two samples exhibits values ($1620 arcsec) which are approximately one order of magnitude higher than the symmetrical ones, implying that the density of threading dislocations (TDs) having an edge component is in the range of 1 Â 10 10 cm À2 . 41 Fig.…”

“…11,12 However, large-size ZnO substrates with high purity are still not available and the application of homoepitaxy for nonpolar ZnO growth is not possible. (1 102) r-plane and (10 10) m-plane sapphire are hence the most popular substrates for the nonpolar epitaxy of ZnO epilayers [13][14][15][16] and QWs. 17,18 Even though the lattice mismatch of 1.6-18.3% for a-plane ZnO on r-plane sapphire is lower than that of 9.4-75% for the m-plane system, high densities of basal stacking faults ($10 5 cm À1 ) and threading dislocations ($10 10 cm À2 ) were observed in the a-plane ZnO epilayers.…”