Amorphous Ga2O3 deep UV imager for label-free biomolecule detection

Biomolecule analysis plays a vital role in early disease diagnosis, personalized nutrition, food science, and basic biomedical research. Yet, current technologies face fundamental trade-offs between each pair of the parameters including sensitivity, throughput and cost. In this work, a scalable platform for biomolecule sensing was proposed based on amorphous gallium oxide (a-Ga2O3) thin film considering its remarkable deep ultraviolet (UV) response property and unique low-temperature compatibility with large-area electronics. A single-pixel a-Ga2O3 photodetector with a peak responsivity of 0.65 A/W at 255 nm was first employed to identify four basic biomolecules including adenine, guanine, L-phenylalanine, and L-tyrosine. The concentration-dependent photocurrent varied in good agreement with their distinct UV absorbance properties verified by a commercial UV-Vis spectrometer. Further, a 64 × 64 deep UV imaging array was constructed by directly depositing the a-Ga2O3 film onto a commercial amorphous silicon (a-Si) thin-film transistor (TFT) backplane, successfully achieving a high-throughput imaging of the four biomolecules. These results establish a viable strategy for a portable, miniaturized and cost-effective biomolecule sensing circuit with rapid and label-free detection.