Active Control of Photon Recycling for Tunable Optoelectronic Materials

Abstract Optoelectronic materials are the backbone of today's high‐tech industry. To customize their response, one can directly modify the atomic arrangement, chemical composition, lattice strain, or doping of the semiconductor. However, these processes frequently cause undesirable effects resulting from induced defects. Here, a novel concept is demonstrated to actively tune the optoelectronic response of a material through tailored photon recycling. Without altering the material's intrinsic structure, doping, or temperature, the reabsorption of emitted photons within GaAs is modulated to control its carrier density. This approach is used to create a diode that can change its emission wavelength, a solar cell with improved open‐circuit voltage, and an actively controlled, gate‐free current modulator. These results represent a new platform to enable materials with tailored optoelectronic response based on photonic manipulation rather than semiconductor engineering.