Microtransfer Printing High-Efficiency GaAs Photovoltaic Cells onto Silicon for Wireless Power Applications

Here, the development of high-efficiency microscale gallium arsenide (GaAs) laser power converters, and their successful transfer printing onto silicon substrates is reported, presenting a unique, high power, low-cost, and integrated power supply solution for implantable electronics, autonomous systems, and Internet of Things (IoT) applications. 300 mu m diameter single-junction GaAs laser power converters are presented and the transfer printing of these devices to silicon is successfully demonstrated using a polydimethylsiloxane stamp, achieving optical power conversion efficiencies of 49% and 48% under 35 and 71 W cm(-2)808 nm laser illumination respectively. The transferred devices are coated with indium tin oxide (ITO) to increase current spreading and are shown to be capable of handling very high short-circuit current densities up to 70 A cm(-2)under 141 W cm(-2)illumination intensity (approximate to 1400 Suns), while their open circuit voltage reaches 1235 mV, exceeding the values of pretransfer devices indicating the presence of photon recycling. These optical power sources could deliver Watts of power to sensors and systems in locations where wired power is not an option, while using a massively parallel, scalable, and low-cost fabrication method for the integration of dissimilar materials and devices.