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The MBE growth and doping of heteroepitaxial layers of lnSb on GaAs (100) are investigated. The layers are assessed by low-field Hall and magnetoresistivity measurements and high-field Shubnikov-de Haas studies together with infrared transmission, and TEM. The mechanism for silicon incorporation is investigated as a function of growth temperature. At low growth temperatures =340 "C) silicon acts only as a donor and can produce electron concentrations up to 3 x 10l8 cm-3 with 77 K mobilities indentical to those found with bulk material. Although higher concentrations than 3 X 10l8 cm-3 can be achieved; auto-compensation appears to occur in those samples. The 77 K mobilities achieved for less heavily doped samples ( > 4 0 000 cm2 V-' S" for n = 1.2 x lo1' cm-3 for samples grown at 340 OC) are the highest lowtemperature mobilities yet reported for n-type lnSb films of = 1 p m thickness grown on GaAs. However, higher growth temperatures (-420 "C) combined with constant silicon flux are found to simultaneously decrease electron concentration and mobility measured at 77 K although the structural quality as assessed by TEM remains unchanged. Analysis of the observed behaviour in terms of the Brooks-Herring model of ionised impurity scattering, modified for non-parabolicity, suggests that silicon is acting amphoterically with compensation ratios (N,/N,) reaching 0.5 at the higher temperatures. The effect of the interface between GaAs and InSb (lattice mismatch = 14%) on the electrical properties is studied by introducing doping slabs of thickness =l300 8, at various distances (d) between the interface (d=O pm) and the surface (d-1.5 pm) of the epilayer. The mobility is degraded by more than a factor of two when the slab is located at the interface but deviations from the bulk mobility are small when the sample is grown at low temperatures and the slab is located more than =0.3 p m from the interface. Pronounced two-dimensional Shubnikov-de Haas effects are observed with the doping slabs. A series of peaks not periodic in reciprocal field (1/B) are found at low fields with B parallel to the slabs and are interpreted as arising from the diamagnetic depopulation of the large number of subbands occupied as a result of the considerable thickness of the slabs. Be doping at 2 x IO'' cm-3 was demonstrated and, as with silicon, the bulk mobility corresponding to this hole concentration was achieved.

Compression tests have been carried out on Ni-rich single crystals of Ni,(AI, Ti) with [OOl] and [ 1321 compression axes over the temperature range -110 t o 1000 "C. The [I321 orientated crystals exhibited a peak in the flow stress a t about 450 "C. Slip line and dimensional analysis revealed five different modes of deformation over t h e temperature range studied. The significant feature of the three deformation modes t h a t occurred below the peak flow stress temperature (450 "C) was the absence of primary cube slip. Suppressing cube slip by compressing along [OOl] was found t o markedly increase the flow stress a t high temperatures and to raise the temperature of the peak. It is proposed that the positive temperature dependence of the flow stress results from a n anomalous increase in the critical resolved shear stress for octahedral slip with increasing temperature, and not from a n interaction between octahedral and cube slip.Es werden Kompressionsuntersuchungen a n Ni-reichen Ni,(AI, Ti)-Einkristallen mit [001]-und [132]-Kompressionsachsen im Temperaturbereich von -110 bis 1000 O C durchgefiihrt. Die in [132]-Richtung orientierten Kristalle zeigen in der FluBspannung bei etwa 450 "C ein Maximum. Die Analyse der Gleitlinien und Abmessungen ergibt fiinf unterschiedliche Deformationsmoden im untersuchten Temperaturbereich. Das wesentliche Merkmal der drei Deformationsmoden, die unterhalb der maximalen Temperatur der FluBspannung (450 "C) auftreten, ist das Fehlen von primarer kubischer Gleitung. Es wird gefunden, daB die Unterdriickung von kubischer Gleitung durch Kompression in [001]-Richtung die Flu& spannung bei hohen Temperaturen merklich erhoht und daB die Temperatur des Maximums anwachst. Es wird angenommen, daB die positive Temperaturabhangigkeit der FluBspannung von einem anomalen Anstieg der kritischen Schubspannung fur oktaedrische Gleitung mit steigender Temperatur herriihrt und nicht von einer Wechselwirkung zwischen oktaedrischer nnd kubischer Gleitung.

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