Inx Ga1 Research Articles

High-field electron transport in InxGa1−xAsyP1−y (λg =1.2 μm)

A fixed-frequency microwave time-of-flight technique has been used to measure electron drift velocities in Inx Ga1−x Asy P1−y (λg =1.2 μm) at temperatures 95–400 K and electric field strengths of up to 200 kV/cm. The room-temperature electron drift velocity in the quaternary is equal to the velocity in GaAs for field strengths greater than ∼62 kV/cm, but the velocity is higher in the quaternary for field strengths from about 20–62 kV/cm at 300 K. At temperatures above 300 K the high-field velocity is larger in the quaternary than in GaAs, but below 300 K the high-field velocity is larger in GaAs.

Efficient LPE-grown Inx Ga1 −x As LEDs at 1–1.1-μm wavelengths

We report the growth and fabrication of LPE multilayer Inx Ga1 −x As homojunction LEDs. Junction edge emission in the 1.0–1.1-μm wavelength range was obtained with external efficiencies of ∼1%. An important feature of the device structure is the incorporation of simple stepwise compositional grading for lattice matching of the substrate and p-n junction layers.

Optical properties of vapor-grown Inx Ga1−xAs epitaxial films on GaAs and Inx Ga1−xP substrates

The absorption coefficients for Inx Ga1−xAs epitaxial n - and p-type films have been determined for the composition range 0 < x < 0.25. The optical absorption coefficient is a parameter in the operation of negative electron affinity (NEA) photoemissive devices, and the experimentally determined absorption coefficient will be useful in the interpretation of NEA photoemissive device characteristics. In general, the optical absorption properties of n - and p-type Inx Ga1−xAs alloys vary smoothly with increasing indium content. The effect of lattice parameter mismatch between the Inx Ga1−xAs epitaxial film and GaAs or Inx Ga1−xP substrates on the optical absorption properties is shown to be negligible. Doping with zinc acceptor impurities ([inverted lazy s]1019 cm−3) does, however, apparently change slightly the characteristics of the Inx Ga1−xAs absorption curves, particularly at low In compositions. Two nondestructive methods of determining the acceptor density of zinc-doped GaAs epitaxial layers have been compared. The plasma minimum method is useful for acceptor concentrations above about 5 × 1018 cm−3, while the free-carrier absorption method gives quantitative values in the 1017–1019-cm−3 range.