Квантовый выход кремниевого лавинного фотодиода в диапазоне длин волн 120-170 nm

The external quantum yield of silicon avalanche photodiode in the wavelength range of 120-170 nm was performed. It was shown that the engineered avalanche photodiode has the external quantum yield of 24-150 electron/proton under reverse bias voltage of 230-345 V, respectively. The testing of worked out avalanche photodiode by means of pulse flash of 280 and 340 nm wavelength demonstrates the speed, corresponding to the bandwidth not less than 25 MHz.

Влияние висмута на свойства упругонапряженных гетероструктур AlGaInAsP<Bi>/InP

The results of growing elastically stressed AlGaInAsP〈Bi〉 thin epitaxial layers from the liquid phase on indium phosphide substrates in a temperature-gradient field are discussed. The effect of bismuth on the structural perfection, the luminescence properties, and the external quantum yield of AlGaInAsP〈Bi〉/InP heterostructures is investigated.

Латеральные наноструктуры Ga(In)AsP как часть оптической системы фотопреобразователей на основе GaAs

The possibility of lateral Ga (In) AsP nanostructures grown by a catalytic method in a quasi-closed volume from phosphorus and indium vapors on the GaAs (100) surface as an antireflection coating for photovoltaic devices is considered for the first time. It is shown that at fixed growth temperature, it is possible to control the surface morphology by changing the growth time. The surface morphology was investigated by scanning electron and atomic force microscopy. The dependence of surface reflection coefficient in the range of 400-800 nm on the surface structure is shown. The use of such coating in GaAs-based photocells demonstrated a significant increase in the external quantum yield of photoconverters.

Спектры люминесценции мощных светодиодов на основе нитрида галлия в ультрафиолетовой и фиолетовой областях спектра

The electroluminescence spectra of high-power light-emitting diodes (LEDs) based on p – n heterostructures of the InGaN/AlGaN/GaN type emitting in the visible short-wavelength and ultraviolet spectral regions (the range from 370 to 460 nm) are investigated. The shape of spectra is described by a model taking into account a two-dimensional combined density of states and potential fluctuations. Additional long-wavelength peaks are found in emission spectra. The emission power of ultraviolet and violet LEDs reaches 233 mW at a current of 350 mA, and the external quantum yield reaches 23% at the maximum (near a current of 100 mA).

Photoelectrochemical properties of n-type KTaO3 single crystals in alkaline electrolytes

Semiconducting KTaO3 single crystals were investigated as a model potential photoanode for hydrogen production using photoelectrochemical cells. To modify the electronic properties of KTaO3 by reducing the band gap and thereby increasing the absorption of light at longer wavelengths, the crystals were doped during growth. A wide range of dopant elements was used that consisted primarily of transition metal atoms. Most of the crystals exhibited n-type behavior with carrier concentrations from 4 × 1018 to 2.6 × 1020 cm–3. The position of the band edges indicated that the crystals were thermodynamically capable of water dissociation. External quantum yield measurements revealed that the samples were photoactive up to a wavelength of ∼350 nm. The indirect band gap and a parameter denoted as E1 that is related to the direct band edge of the semiconductor, were found to be essentially the same for all of the samples. These results indicate that the various dopants and treatments did not produce changes in the KTaO3 electronic structure that were sufficient to significantly modify the behavior of KTaO3 in a PEC cell.

Plastic Multilayered Molecular Organic Light Emitting Diodes

Enhanced performance has been observed for plastic molecular organic light emitting diodes (MOLEDs) consisting of two to four organic layers sequentially vacuum vapor deposited onto patterned indium-tin oxide (ITO) on polyester films. For all device structures studied, the performance of plastic diodes is comparable to or better than their analogs on glass substrates. At 100 A/m2, a luminous power efficiency of 4.4 lm/W and external quantum yield of 2.7% are measured for a device structure consisting of two hole transport layers, a doped emitting layer and an electron transport layer on a polyester substrate. The same device made on a silica substrate has a luminous power efficiency of 3.5 lm/W and external quantum yield of 2.3%. Electrical and optical performance for comparable device structures has been characterized by current-voltage-luminance measurements and electroluminescence spectra collected normal to the emitting surface. In addition, an integrating sphere was used to collect the total light emitted and to determine the optical output coupling on glass versus plastic substrates.