Search

Demonstrates the possibility of injecting minority carriers into a resonant tunneling transistor through a quantum-well base layer. Results of electron injection from the layer; Persistence of the optical output in the differential resistance region of the current voltage characteristics; Use of the transistor as an electro-optical heterodyne convertor.

The Franz–Keldysh oscillations induced by the electric field in the depleted zone below the GaAs surface are studied by photoreflectance spectroscopy. The electric field is precisely controlled by a molecular beam epitaxy grown buried highly doped layer and the pinned position of the Fermi level at the surface. It is shown that the electric field value as derived from theory is in disagreement with the value derived from electrostatic calculations. Consequently a determination of the Fermi level pinning is only possible from a measurement of both n- and p-doped samples. [ABSTRACT FROM AUTHOR]

Photoreflectance spectra have been used to characterize miniband formation in GaAs/ Alx Ga1-x As superlattices with wide wells (275–255 Å) and withb arriers as thin as 17 Å. Thirty-two optical transitions are resolved in the photoreflectance spectra of the 17 Å barrier sample. These experimental transitions match all those theoretically predicted from the selection rule Δn=0, including Γ- and Π-type transitions arising from miniband dispersion; these results imply sample perfection. A sample with a 40 Å barrier exhibits forbidden transitions with Δn≠0; these additional transitions, together with the narrow width of the minibands for 40 Å barriers, create difficulty in resolving the miniband structure. [ABSTRACT FROM AUTHOR]

A gallium arsenide film is grown embedded in masked pre-etched wells in silicon vicinal (001) substrates by molecular beam epitaxy. The morphology and crystallinity of the embedded GaAs on Si layers are identical to those of large area GaAs on Si grown on the same wafer, as indicated by the comparison of Nomarski contrast photomicrographs and electron channeling patterns. High-resolution electron microscope images reveal the epitaxial relation of the GaAs/Si interface on the bottom and the sidewall of the wells. On the slope most of the dislocations are restricted to a narrow region near the interface. The same photoluminescent behavior is found for the GaAs deposit in the different silicon environments. This embedded growth technique is suitable for realization of a coplanar GaAs on Si surface. [ABSTRACT FROM AUTHOR]