Exhibit Quantum Size Effects Research Articles

Single thin-active-layer visible-spectrum In1−xGaxP1−zAsz heterostructure lasers

Single active-layer visible-spectrum In1−xGaxP1−zAsz heterostructure lasers are described that exhibit quantum size effects (QSE) in photoluminescence and by means of diode injection (λ<6300 Å). Liquid-phase epitaxial (LPE) quaternary layers as thin as ∼300 Å have been realized. It is demonstrated that single thin-layer recombination wells (Lz<1000 Å) are very effective in the capture and recombination of carriers, even if injection occurs at some distance (a<1 μm) from the thin layer. On the other hand, optical confinement and absorption are weak in diodes with single active layers thin enough to exhibit QSE. This behavior indicates that the type of thin-active-layer diodes described here are not optimum as lasers, but may lead to improved light emitters.

Single and multiple thin-layer (L z≲400 A) In1−xGaxP1−zAsz-InP heterostructure light emitters and lasers (λ∼1.1 μm, 77 °K)

Liquid-phase epitaxial (LPE) single and multiple thin quaternary layer In1−xGaxP1−zAsz laser diodes (x∼0.13, z∼0.28; λ∼1.1 μm, 77 °K) that exhibit quantum size effects (QSE) are described. LPE quaternary active layers approaching Lz∼200 A have been achieved. As a prototype for the behavior of multilayer heterostructures, the operation of single In1−xGaxP1−zAsz potential wells, or recombination layers, located a small distance into the p side of an InP p-n junction, is considered. Almost all the carrier recombination is observed to occur in the quaternary potential well, and little absorption occurs in the single-active-layer structure, consistent with the small change in the effective index of refraction measured in a large range (1500 A, 150 meV). This general behavior, i.e., single-well recombination, is observed also in thin-active-layer multilayer heterostructures in which the InP layers between quaternary layers are relatively thick (400–1000 A). In multilayered diode structures, distributed feedback may contribute, along with QSE, to modulation of the longitudinal (Fabry-Perot) modes.