Absorption of Infrared Radiation by an Electronic Subsystem of Semiconductor Nanoparticles

Abstract

The frequency dependence of the cross section of photon absorption by semiconductor nanoparticles in the infrared range is considered. Light is absorbed by conduction electrons with plasmon formation and electrons in the traps both within the bulk and on the nanoparticle surface. The regularities of the photoabsorption cross section largely depend on the size of the nanoparticles. For sufficiently large nanoparticles, there appear only two characteristic peaks in the cross section distribution corresponding to light absorption by two types of electronsconduction electrons and electrons in the volume traps of nanoparticles. The number of electrons trapped on the surface is relatively small, and the electrons do not contribute to the total cross section of photoabsorption. In the case of photon absorption by quantum dots, the contribution of these surface electrons as well as a third peak is evident. This result occurs due to a complex dependence of the number of electrons in the traps on their depth and size of nanoparticles.

Green light activated hydrogen sensing of nanocrystalline composite ZnO-In2O3 films at room temperature

“…These states may be shallow and become ionized easily under the green illumination. For example, the existence of shallow traps (about 1 eV below the conduction band) was shown in nanocrystalline In 2 O 3 24 .…”

Sensor Effect in Oxide Films with a Large Concentration of Conduction Electrons

“…To uniquely determine the distribution of conduction electrons inside In 2 O 3 , several parameters were obtained from experiment. In particular, the activation energies ε d = 7.4 × 10 –3 and ε O = 2 × 10 –2 (here and further we use the atomic units) were determined by measuring the sensor conductivity in vacuum and in air. , However, several important parameters, controlling absorption and desorption of oxygen and hydrogen, are unknown. They are obtained by comparing experimental and theoretical temperature dependencies of sensitivity Θ­( P H 2 ; T ) and choosing the values that give the best agreement between experimental and theoretical sensitivities at corresponding temperatures at maxima of Θ­( T ) curves for the case of concentration of hydrogen at 1100 ppm.…”

Absorption of Ultrashort Electromagnetic Pulses by ITO Nanoparticles

“…The conductance and the Seebeck coefficients at different temperatures of heated sample were analyzed. The cross sections of photoabsorption in the IR range by In 2 O 3 nanoparticles were calculated . These studies used as initial data, the number of electrons in traps and distribution of conduction electrons over the nanoparticle radius …”

“…The cross sections of photoabsorption in the IR range by In 2 O 3 nanoparticles were calculated. 17 These studies used as initial data, the number of electrons in traps and distribution of conduction electrons over the nanoparticle radius. 18 In the present study, the probability of photoabsorption of ultrashort electromagnetic pulses is calculated, and a description is given of the method used for measuring the refractive index of the surrounding medium in which an ITO nanoparticle is placed.…”