The effect of piezoelectrically coupled stresses on the junction characteristics of CdS-Cu2S solar cells

An investigation was conducted to determine the effects of piezoelectrically coupled stresses on the capacitance, open-circuit voltage, short-circuit current and I-V characteristics of CdS-Cu2S solar cells. The theoretical analysis suggests that only nonuniform stresses will result in changes in the open-circuit voltage and capacitance. This was consistent with measurements made under uniform and nonuniform stress. Furthermore the direction of the change was consistent with that expected for junctions formed on the polar S face or the Cd face. The short-circuit current and the I–V characteristics are, however, sensitive to both uniform and nonuniform stress but insensitive to the polar face on which the cell is formed. This suggests a nonpiezoelectric stress effect for these characteristics. The measurements were made at relatively low levels of stress (∼2 to 4×107 N/m2) and stress gradients (∼2×1010 N/m3). Under these conditions the measured changes are 1% or less. Thus the built-in stresses resulting from cell manufacture are not expected to have a significant effect on cell properties unless they are at least an order of magnitude larger.