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Bogdanova, E V

Publications and source records attributed to Bogdanova, E V.

2 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Conductivity compensation in p-6H-SiC in irradiation with 8-MeV protons

Carrier removal rate (V{sub d}) in p-6H-SiC in its irradiation with 8-MeV protons has been studied. The p-6H-SiC samples were produced by sublimation in vacuum. V{sub d} was determined by analysis of capacitance-voltage characteristics and from results of Hall effect measurements. It was found that complete compensation of samples with initial value of N{sub a} - N{sub d} Almost-Equal-To 1.5 Multiplication-Sign 10{sup 18} cm{sup -3} occurs at an irradiation dose of {approx}1.1 Multiplication-Sign 10{sup 16} cm{sup -2}. In this case, the carrier removal rate was {approx}130 cm{sup -1}.

36 MATERIALS SCIENCE↗
DOE OSTI2011

Effect of the silicon doping level and features of nanostructural arrangement on decrease in external quantum efficiency in InGaN/GaN light-emitting diodes with increasing current

A comprehensive study of blue light-emitting diodes based on quantum-well InGaN/GaN structures with external quantum efficiencies {eta} of up to 40% has been carried out. It is shown that, in the general case, the manner in which the efficiency depends on the current density j is determined by the competition of contributions to the radiative recombination of localized and delocalized carriers. The contribution of the latter grows with worsening structural organization of the nanomaterial, increasing temperature and drive current, and decreasing width of the depleted layer in the active region (under zero bias). The steepest efficiency droop relative to the maximum value (by up to a factor of 2 at j Almost-Equal-To 50 A cm{sup -2}) is observed in the case of heavy doping of the n{sup +}-region (to 10{sup 19} cm{sup -3}) and upon appearance of compensated layers in the active or p{sup +}-region. At j > 50 A cm{sup -2}, the contribution of delocalized carriers is predominant and the current dependences of efficiency are of uniform type, approximated with {eta}(j) {proportional_to} j{sup -b}, where 0.2 < b < 0.3.

36 MATERIALS SCIENCE↗