Simulation of Electrothermal Characteristics of SSI-LEDs

Abstract

The temperature distribution in nano-resistors based solid-state incandescent light emitting devices made from MOS capacitors with a high-k gate dielectric deposited on the p-type Si substrate is studied using finite element modeling. The results obtained are correlated with experimental data previously reported on the device. The physics-based mathematical formulation with governing equations was simulated using the COMSOL Multiphysics program. Temperatures within and around individual nano-resistors in different geometrical arrangements, distributions and sizes were calculated. The temperature distribution across the complete device under various boundary conditions was simulated and optimized based on the optical emission spectrum of the device.

Comparison of simulated and measured light emission spectra from solid state incandescent light emitting devices

“…This is consistent with the earlier studies suggesting that the color-correlated temperature (CCT) of the SSI-LED lies typically between 2500K and 4500 K, which is a function of gate voltage, dielectric material, and processing parameters [26]. Additionally, electrothermal calculations under certain assumptions have been performed earlier to estimate temperatures in and around the conductive paths formed in the gate dielectric [23]. Hence, radiation spectrum of a blackbody at 4,000 K is exploited for the further study on the effect of the thin film filter on the emission spectra calculated theoretically from the Planck equation and light absorption data, are measured experimentally.…”

“…al. [23]. The determination of optical transmittance of molten ITO over the visible and IR wavelengths might help in achieving more precise comparisons.…”

“…The peak of the theoretical spectrum with a-Si thin film filter was found to be off towards the long wavelength range compared to the experimentally recorded spectrum. This deviation may be attributed to the fact that the a-Si thin film melts from the intense heat conducted from underneath nano-resistors [23]. It is highly likely that the a-Si film over the nano-resistors recrystallizes and forms poly-Si at such high temperatures.…”

“…Moreover, the emission spectrum can be transformed into a major narrow peak at 850 nm with a bandwidth of ~8 nm and a minor peak of 650 nm using a 9-layer (HL) 2 HH(LH) 2 Fabry-Perot filter where H and L are 52.0 nm thick a-Si:H film and 105.9 nm thick SiNx film, respectively [10]. Additionally, Shukla and Kuo recently reported that the equivalent blackbody temperature of nano-resistors, formed in the high-k dielectric thin film, responsible for the light emission is around 4,000K [23].…”

Simulation of Light Intensity and Nano-Resistor Distribution in SSI-LEDs Using Python as a Framework

“…20 COMSOL Multiphysics was used to simulate the steady state operation of an SSI-LED with a few NRs of fixed sizes. 23,24 The program uses the Finite Element Method to solve systems of differential equations for a control volume defined by the boundary conditions at the exterior surfaces of a 3D model. The COMSOL simulations have a number of limitations.…”