Electron hole plasma

At low temperatures a pure semiconductor is a perfect insulator with no free carriers. Upon laser irradiation at a frequency greater than the semiconducting band gap, a high density of electron-hole pairs can be excited which, at liquid-helium temperatures, condense into small droplets of electron-hole plasma. These electron-hole (e-h) droplets have been discussed thoroughly in a dedicated volume of Solid State Physics that contains reviews of theoretical aspects (Rice, 1977) and experiments (Hensel et al., 1977). 

A survey of the optical bandgap, excitonic recombination properties under low excitation and electron hole plasma recombination in AlxGai.xN has been given. Demand for UV applications, i.e. gas sensors or monitors, flare sensors, medical applications, chemical and biochemical applications and light sources for phosphors increases rapidly, which will surely lead to the further improvement of the quality of the AIN containing nitrides, and thus give us much more information about their luminescence properties. 

When we wish to verify the lasing operation of a new and/or ultra-low threshold device, the non-linear relation in the injection current versus light output characteristics is an easy method of testing the threshold criterion. However, sometimes this is observed even on non-lasing samples owing to the filtering effect and electron-hole plasma emission. Methods used to definitively confirm laser operation for vertical cavity devices are as follows [37] ... 

The creation of photons or specific (e.g., squeezed) states of the electromagnetic held due to the motion of some effective mirrors made of the free electrons moving with (ultra)relativistic velocities was studied [206-207]. Another kind of effective moving mirror consisting of the electron-hole plasma generated in semiconductors under the action of powerful laser pulses was also suggested [208,209]. 

Additionally, ELT MQW heterostructures were grown and studied. Fig. 2, cinve 1 shows an EL spectrum imder forward bias. The low-energy shift of the EL spectrum comparing to the PL spectra (curves 2-5) evidences a lower carrier concentration at electrical excitation and recombination via localised states in the quantum wells (In rich clusters or quantum dots). At high optical excitation, the delocalised states (electron-hole plasma) play the most important role in the QW emission. 

Semiconductor (electron-hole plasma) GaAs 890 E- beam, laser pumping... 

K. Kimura, Ultra fast luminescence in heavy-ion track-cores in insulators Electron-hole plasma, Nucl. Instr. Meth. Phys. Res. B191, 48 (2002)... 

Thereafter it has been stressed that the mechanism of diffusion driven instability is pertinent to the formation of dissipative structures in other fields electron-hole plasmas in semiconductors [12], gas discharge devices [13], semiconductor structures (p-n junction, p-i-n diodes) [14], heterogeneous catalysis [15], materials irradiated with energetic particles or light [16-18],... 

Appropriate initial and boundary conditions should also be added to complete the mathematical formulation. In Equation (1) C(r,t) is the local concentration vector, F(C 5) a vector function representing the reaction kinetics, B stands for a set of control parameters and D is the matrix of transport coefficients. In most chemical systems involving small molecules in aqueous solutions, the diffusion processes are well described by a diagonal matrix with constant positive diffusion coefficients. However, in some systems it is the coupling between the transport processes that provides the engine of the instability. For instance, stratification occurs in electron-hole plasmas in semiconductors subjected to electromagnetic radiations because of the effect of the temperature field on the carrier density distribution (thermodiffusion)... 

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