  Like many optoelectronics, the highest quality III-V solar cells start out as
thin single-crystalline multilayers on GaAs substrates. Separating these device
layers from their growth substrate enables higher performing devices and wafer
reuse, both of which are critical for III-V solar cell viability in a
terrestrial market. Here, we remove rigidly-bonded, lattice-matched, 16 mm$^2$
x 3.5 um thick GaAs devices off a GaAs substrate using a 10 ns, unfocused
Nd:YAG laser pulse. The pulse is selectively absorbed in a lower-bandgap,
lattice-matched, crystalline layer below the device, driving a quasi-two
dimensional ablation event that ejects the crystalline multilayer from the
substrate. After minutes of selective wet-chemical etching and front contact
deposition, our champion 0.1 cm$^2$ device showed a (17.4 +/- 0.5) % power
conversion efficiency and an open-circuit voltage of 1.07 V, using AM1.5 direct
(1000 W m$^{-2}$) with no anti-reflection coating. We show that the performance
is comparable to similar solar cells produced via conventional substrate
dissolution processes. We discuss unique process characteristics and
opportunities, such as the potential to separate wafer-sized thin film solar
cells per laser pulse.
