The optical properties of a structure with a periodic system of 100 InGaN quantum wells separated by nontunneling GaN barriers are investigated at room temperature. The structure periodicity ...corresponds to the Bragg-diffraction condition at the quantum-well exciton frequency. The results of numerical simulation using transfer matrices are in reasonable quantitative agreement with the experimental data. The model includes the resonance response of A, B, and C excitons in the quantum wells and the optical absorption tail in the barrier and buffer layers. The radiative and nonradiative damping rates of excitons in the InGaN quantum wells are determined.
•Si3N4 deposition from SiH4 and NH3 in III-N MOVPE reactors is studied.•Si3N4 deposition rate rises with temperature up to 1050–1100 °C.•Under any studied conditions Si3N4 deposition rate is linear ...with SiH4 concentration.•The higher the pressure is, the faster the Si3N4 deposition is.•Under H2 ambient deposition rate rapidly rises with NH3 flow and then gradually falls.
Si3N4 deposition from silane and ammonia in a number of III-N MOVPE reactors of various sizes was studied in a wide range of reactor conditions. It was revealed that Si3N4 deposition rate depends on temperature, pressure, carrier gas type, and ammonia concentration. Deposition rate rises with temperature up to 1050–1100 °C in a manner typical for temperature-activated processes, but under any studied conditions, including the 800–850 °C range, it is strictly linear with SiH4 concentration indicating the absence of high-order parasitic reactions at high temperature and surface passivation at low temperature. For a low-volume reactor the higher the pressure is, the faster the deposition is both for N2 and H2 carrier gases. For large reactors the dependence is non-monotonic. At temperature above 900 °C using H2 as a carrier gas results in a higher Si3N4 deposition rate than when using N2. If nitrogen is used as a carrier gas, deposition rate gradually rises with ammonia concentration. If hydrogen is used, deposition rate rapidly rises with ammonia concentration and then gradually falls. If hydrogen-nitrogen mixture is used as a carrier gas, deposition rate changes in a linear manner with the mole fraction of hydrogen in the carrier gas.
The broadening of the spectral linewidth of the GaN/InGaN/GaN quantum wells caused by the random distribution of indium and gallium atoms in the cation sublattice was analyzed theoretically. The ...calculated values of the full width at half maximum of the emission spectra at low temperature are much smaller than the usually observed experimental values, indicating that the emission linewidth of the InGaN quantum wells is mostly determined by other broadening mechanisms (e.g. indium clustering, quantum well width fluctuations, background impurity broadening, etc.).
InGaN-based dichromatic light emitting diodes (LEDs) emitting in the blue and cyan spectral ranges simultaneously, are investigated both experimentally and theoretically. Two main approaches to ...controlling the ratio of blue-to-cyan components in the emission spectrum are suggested and analyzed: (i) thickness variation of the GaN barrier between the blue and cyan quantum wells and (ii) optimization of the barrier doping with n- or p-type impurities. Detailed examination of the approaches is carried out in order to understand their capabilities for intentional variation of the blue-to-cyan ratio in a wide range. Based on numerical simulations, a novel mechanism, invoking enhanced Shockley-Read-Hall recombination in the barrier and underlying both approaches, is suggested and discussed. It is shown that proposed design of the monolithic blue-cyan LEDs does not result in substantial decrease of the LED emission efficiency compared to monochromatic blue or cyan reference samples.
The optical reflectance and transmittance spectra of a periodic InGaN semiconductor heterostructure with 100 quantum wells are studied at room temperature. Numerical modeling with a single set of ...parameters gave a quantitatively accurate fit of the experimental reflection and transmission spectra in a wide wavelength range. The radiative decay parameter is determined to be 0.25 meV and the nonradiative decay parameter is 40 meV.
Abstract
The influence of two types of AlN/GaN interfacial non-idealities, namely unintentional Ga incorporation into AlN spacer and blurring of the spacer due to Al and/or Ga atomic diffusion on the ...mobility and density of two-dimensional electron gas in AlGaN/AlN/GaN heterostructure was studied theoretically. It was found that moderate amount of GaN in the nominal AlN spacer does not affect much the mobility and density of 2DEG as long as the interface is abrupt. In contrast, the blurring of AlN/GaN interface was found to have a significant impact on the mobility and sheet resistance of the structure since the GaN channel actually becomes AlGaN and alloy-disorder scattering takes place.
A GaN/AlGaN Resonance Bragg Structure Ivanov, A. A.; Chaldyshev, V. V.; Zavarin, E. E. ...
Bulletin of the Russian Academy of Sciences. Physics,
06/2023, Letnik:
87, Številka:
6
Journal Article
Recenzirano
Room-temperature reflectance spectra are recorded for a resonant Bragg structure with 30 GaN/AlGaN quantum wells. Accurate quantitative fitting of the experimental results is achieve by means of ...transfer matrix numerical modeling. Parameters of radiative and nonradiative exciton broadening in the GaN/AlGaN quantum wells are determined.
The effect of annealing temperature and time on the luminescence intensity of the InGaN/GaN heterostructure subjected to ion beam etching was studied. We show that annealing at a temperature of ...1100°C makes it possible to eliminate the radiation defects in the GaN layers that arise in the etching process with a focused Ga
+
ion beam (30 keV).
Selective Epitaxy of Submicron GaN Structures Lundin, W. V.; Tsatsulnikov, A. F.; Rodin, S. N. ...
Semiconductors (Woodbury, N.Y.),
12/2019, Letnik:
53, Številka:
16
Journal Article
Recenzirano
The effect of the growth temperature and the flow of trimethylgallium on the process of selective epitaxy of gallium nitride in windows of submicron size have been studied. The conditions under which ...homogeneous nucleation and coalescence of nuclei are combined with a low growth rate are determined. The steady growth of variously oriented gallium nitride strips with a height of 50 nm and a width of 600 nm was realized.
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