Mobilities similar in magnitude to bulk silicon mobilities may be realized in 1.4 to 1.6µ thick films on flame fusion magnesium aluminate spinel, for carrier concentrations greater than ≈2×1016 cm−3 (p‐type). The electrical properties of these films are not significantly altered by thermal oxidation at 1200° C for 1 hr. In this carrier concentration range the electrical characteristics are not highly dependent on the deposition rate within the limits investigated. For carrier concentrations between 5×1015 and 2×1016 cm−3 (p‐type) the “as deposited” film mobilities are near bulk values, but the mobilities are degraded by the thermal oxidation. In this doping range the electrical properties of the oxidized films are critically dependent on the deposition rate. The films deposited at the higher rates are altered less on oxidation than films deposited at the lower rates. Using a growth rate of 2 µ/min, a mobility of 300 cm2/V‐sec (≈80% of bulk) at Nnormala=4×1015 cm−3 may be realized in a film oxidized 1 hr at 1100°C. Below this carrier concentration the mobility of the oxidized films decreases sharply with decreasing carrier concentrations. Minority carrier lifetimes as high as 40 nsec have been realized in 4µ thick films of silicon on spinel. The carrier concentration as a function of temperature and mobility as a function of thickness of silicon on spinel have been measured.

It was found that GaAs1−normalxPnormalx :Te doped layers can be homogenously transported by a vapor phase technique using water vapor. Epitaxial layers of the same As‐P ratio as the melt‐grown source wafers were grown onto false[trueI¯trueI¯trueI¯false] and [100] normalGaAs substrates. The reaction proceeds via the following equation 2GaAs1−normalxPnormalx+H2O⇄Ga2O+)(1−normalx As2+)(X P2+H2 Ga2O is the actual transporting species. At a water vapor pressure of 0.286 mm (ice at −30°C) an activation energy of 85 kcal/mole was calculated. The amount of material transported was found to be a function of false(afalse)PH2o entering the system, (b) the temperature difference between source and substrate, (c) the composition of the source material, and of course (d) the absolute source temperature. The transport of normalGaAs with water vapor was found to have an activation energy that is nonconcentration dependent within the range of water vapor pressures studied. Certain aspects of Te doping were studied; the oxygen content of the epitaxial layers was studied via mass spectrographic techniques.

Microknot resonators (MKRs), locally fused using a two-probe technique, have exhibited significantly improved optical performance and mechanical stability. They have been operated with low losses both in situ and as transferred devices. We found consistently more than threefold dynamical range enhancement, which remained stable in time, in electrically fused MKRs. These devices can be harbored in next-generation optical sensors, actuators, and optomechanical applications incorporating MKR-assisted microstructures taking advantage of this simple and robust fusing technique.

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