A band diagram and distributions of carrier concentrations of the hybrid ZnO-based LEDs at j = 50 A/cm2
Light extraction efficiency of DUV-LED
Light extraction efficiency of DUV-LED

Modeling of Semiconductor Devices

STR offers dedicated software tools for modelling and optimization of optoelectronic and electronic semiconductor devices:

SiLENSe for 1D drift-diffusion analysis of electron and hole injection into the active region and their radiative and non-radiative recombination. Several recombination channels are considered including Auger recombination and recombination on threading dislocations inherent in Group-III nitride heterostructures.

SpeCLED for coupled 3D analysis of the current spreading and heat transfer in planar and vertical LED chips. Hybrid 1D/3D approach allows fast and stable computations even for complex 3D LED geometry like multi-pixel LED array. SpeCLED uses computational results obtained by SiLENSe to specify the current density, IQE, emission wavelength, etc. as a function of local bias applied to the active region and local temperature. SpeCLED is a powerful tool for design and optimization of the LED chip design, which helps to mitigate such important issues as current crowding, local overheating, non-radiative surface recombination at the chip sidewalls of micro-LEDs.

RATRO for 3D ray-tracing simulation of light propagation, absorption, and extraction from LED chip. RATRO uses the information on the lateral light emission intensity distribution in the LED active region obtained by SpeCLED and computes the output light intensity and optical losses for all the chip surfaces, as well as far-field distribution and light-extraction efficiency (LEE). RATRO provides a great variety of optical boundary conditions at the internal and external chip surfaces, such as multiple layers of metal or dielectric materials including anti-reflective coatings and DBRs, patterned surfaces, etc. This powerful tool for analysis of light extraction, which helps to determine the key factors limiting LEE and virtually try different approaches to overcome them.

BESST software for bandgap engineering of III-nitride based superlattices, which allows to simulate both individual superlattices and LEDs made entirely from superlattices.

FETIS software for modeling of III-nitride high-electron mobility transistors (HEMTs), including:

  • 1D analysis of the band diagram and channel concentration by self-consistent solution of Poisson and Schrodinger equation; 
  • simulation of the transistor characteristics within the gradual-channel approximation using 1D results for band diagram and carrier concentration.

PVcell for simulation of single-junction and multi-junction solar cell heterostructures based on different materials: III-nitride, cubic III-V, Si, and Ge.



LED chip design
Light extraction efficiency of DUV-LED