Effects of the number of periods on strain in superlattices

Abstract

Structural properties and spatial ordering in multilayered ZnMgTe/ZnSe type-II quantum dot structures J. Appl. Phys. 111, 033516 (2012) Piezoelectric superlattices as multi-field internally resonating metamaterials AIP Advances 1, 041504 (2011) Effect of built-in electric field on the temperature dependence of transition energy for InP/GaAs type-II superlattices J. Appl. Phys. 110, 123523 (2011) Polarization property of deep-ultraviolet light emission from C-plane AlN/GaN short-period superlattices Appl. Phys. Lett. 99, 251112 (2011) Tunable superlattice in-plane thermal conductivity based on asperity sharpness at interfaces: Beyond Ziman's model of specularity J. Appl. Phys. 110, 113529 (2011) Additional information on J. Appl. Phys. The effect of periods on the accumulation and release of stress in GaAs/AlInAs superlattices structure is reported here. It is observed that in GaAs/AlInAs superlattices, when the Indium ͑In͒ content is greater than 10%, stress accumulates monotonically as the number of period increases. In GaAs/AlInAs superlattices with an In content of 5%, the accumulated stress is larger when the number of periods is less than 10. However when the number of periods exceeds 10, it was observed that suddenly there is a significant increase in defects and stress release. However, with any further increase in period number, there is once again an accumulation of stress.

Mechanism of Nano-Structuring Manipulation of the Crystallization Temperature of Superlattice-like [Ge8Sb92/Ge]3 Phase-Change Films

“…Zhou et al proposed that stress was intentionally introduced into SLL phase-change films [GeTe/Sb 2 Te 3 ]n to lower melting temperature and further lower the RESET power consumption [ 50 ]. Based on our stress mechanism, the effect of the cycle number of periods on the crystallization temperature of SLL films can also be explained well because it was reported that the variation of cycle number in SLL films could lead to the accumulation and release of stresses [ 19 , 43 ]. Up to date, the stress and interfacial effects should coexist in SLL phase-change films.…”

“…Stress is a long-range force and is ubiquitous in film materials due to lattice mismatch between two different constituent layers in SLL films and between sample films and substrates. Stress is influenced not only by film thickness [ 22 , 41 , 42 ], but also the cycle number of periodicity in SLL films [ 43 ], which is an apparent long-range effect. As a result, in our case, the variation in the Ge layer’s thickness may change the stress in SLL films, [Ge 8 Sb 92 /Ge(x)] 3 (x = 2, 5, 8 and 11 nm).…”

“…The currently reported main methods to measure stresses in thin films include beam curvature, Raman scattering spectroscopy, and X-ray diffraction [ 42 ]. Raman scattering spectroscopy is considered a simple and reliable method to measure stresses in thin films and has been widely applied in the measurement of stresses in thin films and superlattice films [ 41 , 43 , 44 , 45 , 46 , 47 ]. The measurement of stresses with Raman scattering spectroscopy is based on the shift of a Raman scattering peak in stressed films with respect to the Raman scattering peak in stress-free films [ 41 ].…”

“…The vibration frequency of C mode increases monotonously with increasing x and approaches the vibration frequency (300 cm −1 ) of the Ge–Ge bond in 100 nm thick Ge film, and thereby, it is attributed to the vibration mode of Ge–Ge bonds [ 48 ]. The frequency shift of phonon modes with film thickness is a typical feature of stress effect, and is studied widely in various films [ 35 , 43 , 44 , 45 , 46 , 47 ]. Consequently, our Raman experiments confirm the presence of stress in our SLL films.…”