Effect of Multijunction Approach on Electrical Measurements of Silicon and Germanium Alloy Based Thin-Film Solar Cell Using AMPS-1D

Abstract

Multijunction solar cells designed from silicon (Si)-germanium (Ge) alloy based semiconductor materials exhibit high theoretical efficiencies (19.6%) compared to the single junction one. The modeling calculations for all solar cells are done by AMPS 1D simulator. The structure of multi-junction i-layer is designed using heterolayers, starting from pure crystalline Si and increase of Ge mole fraction by 25% until pure Ge layer is reached. The top layer has the largest band gap, while the bottom layer has the smallest bandgap. This design allows less energetic photons to pass through the upper layer(s) and be absorbed by the layer below, which increases the overall efficiency of the solar cell. Material parameters required to model the absorber layers are calculated and incorporated in the AMPS 1D simulator for optimizing of solar cell parameter values. Simulation results show that considerable efficiency enhancement can be obtained from the addition of the multi-junction layer.

Heterostructure Silicon and Germanium Alloy Based Thin Film Solar Cell Efficiency Analysis

“…8 we can conclude that current density of device is increasing with decrease in Ge mole fraction. But again due to trapping and absorption phenomenon the curve behaves exceptionally for the Ge mole fraction" 0.15" and produce maximum current density of 382.50 A/m2 resulting in open circuit voltage of 0.56 V. The important cell electrical parameters which contributes in efficiency of solar cell are short circuit current density ( ) , open circuit ( ), maximum output power ( ) and fill factor (FF) [8,9,10]. The maximum output power can be calculated through fig.…”

MATLAB User Interface for Simulation of Silicon Germanium Solar Cell

“…According to Maxwell-Boltzmann approximation, depends on (effective density of states in conduction band) where SiGe is the intrinsic carrier concentration, is the energy band gap, and is the Ge mole fraction [11]. The …”

Analysis of Si/SiGe Heterostructure Solar Cell

“…States Density. Using Maxwell-Boltzmann approximation in equilibrium state for the carrier concentrations as a function of the Fermi level, carrier concentrations can be represented as [6,7]…”

“…of thin SiGe film, the absorption rate shoots high and more electron hole pair can be generated due to the incident light. Generation of a higher number of electron hole pairs implies higher short circuit current density and efficiency of SiGe solar cell [7]. Figure 9 shows the absorption coefficient as a function of wavelength for the standard global AM1.5 spectrum.…”

“…This is due to the energy band structure characteristic of SiGe. It can be observed that there is a drastic increase of the photocurrent sc [7]. Consider Efficiency = sc × oc × ,…”