The gain behavior of GaAs photoconductors realized on the partly compensated channel of a MESFET is studied. The gain versus light power dependence hints at the domination of the bimolecular recombination and the trap-mediated gain, and only a minor role of the surface photovoltaic effect. The possible correlation between dark current and gain mechanism is pointed out.
The transmission characteristic of barrierless ABABA multilayer system, where A and B are materials with differing effective masses, is analyzed. The system shows resonant transmission similarly to a conventional double-barrier system, but shows unique features: unity transmission at zero energy, a more structured nature of the transmission versus energy curve and a non-decreasing peak-to-valley ratio with increasing energy.
Interdigital, planar photodetectors were fabricated from annealed GaAs/Si heterostructures grown by molecular beam epitaxy using alloyed AuGe/Ni and non-alloyed Cr/Au contacts. The dark current and optical gain of the Cr/Au devices is higher than that of the AuGe/Ni devices. Contact degradation due to annealing and a p-like background doping consistently explains our data. The gain-optical power relationship follows a power law with an exponent close to -1.
We investigated current-voltage characteristics of a lattice-mismatched GaAs(n)/Si(p) heterojunction. For low bias voltages at 77 K it exhibits a behaviour characteristic of the Coulomb blockade. We discuss why this unexpected phenomenon can occur in the investigated structures.
The strain relaxation kinetics of ZnTe/CdTe and CdTe/ZnTe heterostructures grown on GaAs substrates by molecular beam epitaxy are studied by in situ reflection high-energy electron diffraction. The observed critical layer thickness is 5 monolayers for ZnTe/CdTe and less than 1 monolayer for CdTe/ZnTe. The relaxation is anisotropic. Dislocation core parameters and relaxation rate constants were determined using a kinetic model and assuming strain-dependent activation energy of dislocation movement.
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.