G. A. Antypas

Bandgap and lattice constant of GaInAsP as a function of alloy composition

AbstractPublished data for the composition dependence of the room-temperature bandgap (Eg) and lattice constant (ao) in the pseudobinary GayIn1-yAs, GayIn1-yP, GaAsxPl-x, and InAsxPl-x systems have been used to derive the following equations for the quaternary GayInl-yAsx Pl-x, alloys:

Glass−sealed GaAs−AlGaAs transmission photocathode

\begin{gathered} a_o ({\AA}) = 5.87 + 0.18x - 0.42y + 0.02xy \hfill \\ E_g (eV) = 1.35 - x + 1.4y - 0.33xy - (0.758 - 0.28x)y(1 - y) \hfill \\ - (0.101 + 0.109y) x(1 - x). \hfill \\ \end{gathered}

Dependence on Crystalline Face of the Band Bending in Cs2 O‐Activated GaAs

Available experimental data are in excellent agreement with these equations.

Photocapacitance effects of deep traps in n‐type InP

Decomposition of InP prior to and following liquid phase epitaxial growth can be completely eliminated by locally providing an increase in P partial pressure compared to that at the InP liquidus. The increase of P partial pressure is a result of increased P solubility in In‐Sn‐P solutions.Decomposition of InP prior to and following liquid phase epitaxial growth can be completely eliminated by locally providing an increase in P partial pressure compared to that at the InP liquidus. The increase of P partial pressure is a result of increased P solubility in In‐Sn‐P solutions.

Liquid phase epitaxial growth of InGaAsSb on (111)B InAs

A GaAs/GaAlAs/GaAs/GaAlAs heterostructure has been prepared on a GaAs susbtrate, bonded to 7056 Corning glass, and the substrate and first AlGaAs removed chemically, utilizing the differential etching characteristics of GaAs and AlGaAs in NH4OH−H2O2 and HF solutions. The resulting structure of GaAs/AlGaAs/glass has excellent layer morphology, uniform thickness, and good transmission photocathode performance.

High‐quantum‐efficiency photoemission from an InGaAsP photocathode

Abstract The conditions for LPE-growth of In 0.53 Ga 0.47 As lattice matched to InP and growth of InP on In 0.53 Ga 0.47 As are discussed. The distribution coefficient of Ga in the In-Ga-As melt is about 6.12. To prevent grading of the InGaAs layer due to depletion of Ga from the melt near the solid-liquid interface, the growth rate has to be reduced to about 0.06 μm/min. Higher growth rates give rise to hillocks on the surface. High purity InGaAs layers have been obtained using In,Ga, and As in the elemental form to prepare the melt and baking the melt prior to growth.

Photoemission from cesium‐oxide‐activated InGaAsP

Electron energy loss in the band‐bending region of the p‐type III–V semiconductor in a III–V photocathode is an important factor in determining the escape probability and the optimum doping. From measurements of photoelectric yield near threshold from Cs2O‐activated n‐type GaAs, the position of the Fermi level at the GaAs–Cs2O interface was determined for {110}, {100}, {111A}, and {111B} surfaces. Assuming the Fermi‐level position at the GaAs surface to be independent of doping, the band bending for p‐type GaAs is greatest for the {111A} face and least for the {111B} face. The measured escape probabilities of photoexcited electrons from different crystalline faces of optimally activated 5 × 1018/cm3 Zn‐doped liquid epitaxial GaAs correlate well with the band‐bending measurements. The {111B} sample has an escape probability of 0.489 and a luminous sensitivity of 1837 μA/lm.

Photoluminescence characterization of solution and lec grown InP

Deep trapping centers in n‐type InP samples grown by the liquid‐encapsulated Czochralski, liquid‐phase‐epitaxial, and vapor‐phase‐epitaxial processes have been studied by photocapacitance techniques. Photocapacitance effects for Schottky barriers formed on these samples indicate four levels at 0.58, 0.78, 0.89, and 1.15 eV below the conduction band. Estimated trap concentration in various samples range from low‐1014 cm−3 to the high‐1012 cm−3. The broad increase in photocapacitance near 1.15 eV for all the samples may be associated with an intrinsic defect or phosphorus vacancy/impurity complexes. This result is consistent with the broadband present between 1.08 and 1.25 eV in photoluminescence experiments. The comparison between O2‐doped and undoped VPE samples suggests the presence of oxygen located at about 0.78 eV below the conduction band in VPE material.