Guiding crack propagation in GaAs solar cells with four-pointed-star patterned GaAs/Si virtual substrate

Abstract This study reports experimental results for GaAs solar cells grown on patterned and unpatterned GaAs/Si virtual substrates. GaAs solar cells grown on Si commonly suffer from cracking induced by thermal-expansion mismatch during growth and cooldown. To mitigate this issue, a four-pointed-star hole array is patterned into the GaAs/Si virtual substrate. The tips of the holes act as crack-steering features that guide cracks along predefined paths away from active regions. The GaAs solar cell on the patterned virtual substrate achieved a V OC of 0.88 V, a J SC of 22.85 mA cm −2 , and an efficiency of 15.10%, whereas the device on the unpatterned virtual substrate exhibited lower values of 0.81 V, 21.51 mA cm −2 , and 11.23%, respectively.