Search

High-speed optoelectronic effects, caused by interconnection between the picosecond stimulated emission and the kinetic processes in dense hot electron-hole plasma in GaAs, are briefly reviewed. The newest effect of this class is reported in detail. It deals with the band gap narrowing as a result of generation of multi-component plasma in GaAs. The plasma is generated by a picosecond light pulse and the picosecond stimulated emission is observed. In this situa-tion, the total concentration of the pairs of photogenerated electrons and holes is experimentally proved to be the only parameter defining the electron distribution between Γ 6- and L6-valleys and the corresponding narrowing of the band gap. This is explained by the fact that in the presence of the emission the temperature and concentration of the charge carriers are approximately bound.

A number of optoelectronic threshold effects arising under intensive stimulated radiative recombina­tion of hot dense electron-hole plasma (EHP) in a thin (~1um) epitaxial layer of GaAs has been revealed. These effects' build-up and decay time intervals are of ~10 ps or less at room temperature (which makes it possible to modulate the optical and electrical properties of semiconductor heterostructures and devices with a frequency of ~ 100 GHz). These effects are observed when the stimulated recombination emission appears in picoseconds. The emission intensity can be as high as ~108 W/cm2 and the EHP concentration can change several times by magnitude. The revealed class of optoelectronic effects has its origin in strong mutual influence between the stimulated emission and dynamical processes in dense EHP. The acquired knowledge of somewhat uncommon mechanism of changes of EHP concentration and temperature, of in­tensity and spectrum of stimulated emission, of the gain, transparency, band-gap width, etc. can be used for successful construction of semiconductor high-speed powerful optoelectronic devices (such as semi­conductor lasers and superluminescence diodes, semiconductor light-wave converters, modulators of the optical transparency and photoconductivity7)

A number of optoelectronic threshold effects arising under intensive stimulated radiative recombina­tion of hot dense electron-hole plasma (EHP) in a thin (~1um) epitaxial layer of GaAs has been revealed. These effects' build-up and decay time intervals are of ~10 ps or less at room temperature (which makes it possible to modulate the optical and electrical properties of semiconductor heterostructures and devices with a frequency of ~ 100 GHz). These effects are observed when the stimulated recombination emission appears in picoseconds. The emission intensity can be as high as ~108 W/cm2 and the EHP concentration can change several times by magnitude. The revealed class of optoelectronic effects has its origin in strong mutual influence between the stimulated emission and dynamical processes in dense EHP. The acquired knowledge of somewhat uncommon mechanism of changes of EHP concentration and temperature, of in­tensity and spectrum of stimulated emission, of the gain, transparency, band-gap width, etc. can be used for successful construction of semiconductor high-speed powerful optoelectronic devices (such as semi­conductor lasers and superluminescence diodes, semiconductor light-wave converters, modulators of the optical transparency and photoconductivity7)