Heterojunction AlGaAs-GaAs solar cells for space applications.
Two types of solar cell AIGaAs-GaAs structures which are heteroface and triple
heterojunction are investigated in this study.
A complete theoretical study including optimisation for the optical properties
( transmission and reflection) of the heteroface AlO.8 GaO2. As- GaAs space solar cell
is presented. The grid shadow and window layer effects, angle of incidence and the
effects of the layer design parameters for AR-coating and window layer on the optical
properties are considered in the calculations.
A new structure for space solar cell which consists of double heterojunction AlGaAs-
GaAs structure with GaAs/AlGaAs heterojunction back surface field (triple
heterojunction(THJ))-to enhance the performance of the existed double heterojunction
solar cell- is proposed. The analytical model for this THJ cell is presented as a
function of all the cell's design parameters ( such as layers doping, thicknesses, etc).
The calculated results for this structure is compared with the experimental results for
the previous double heterojunction structure. The effects of the design parameters of
all layers including the AR-coating on the cell's output performance and the
optimisation conditions are studied as well.
The techniques of the light trapping and the photon recycling( which are good for
space solar cells) are applied for the THJ thin film AIGaAs-GaAs structure to
improve further the efficiency. The change of the optimisation conditions due to the
usage of these two techniques is also discussed.