Integrated GaN Prism Array Self-Powered Photodetector on Si for Ultraviolet Imaging and Communication

To realize the advantageous combination of microelectronic integrated circuit technology and photonic technology, the development of high-speed, low-power, and chip-integrated photodetection devices is extremely critical. Here, a large-scale on-chip integration photodetector array on a Si wafer consisting of 21x21 GaN p-n homojunction pixels is prepared. The GaN homojunction subunit has significant photovoltaic performance at a bias voltage of 0 V, including high responsivity of 229.5 mA W-1, outstanding specific detectivity of 2.46x1013 Jones (360 nm, 45.7 mu W cm-2), and fast response speed of 240/290 mu s. Especially, external quantum efficiency can reach 94% in the faint UV illumination at 0 V bias. The excellent photoresponse is confirmed by finite element analysis, which is resulted from an oversized built-in potential at the p-n homojunction interface. For exploring potential practical applicability of the device, the full range of active pixels is statistically analyzed. It is confirmed that the small relative deviation of the GaN array is extremely favorable for obtaining high-resolution imaging capability. Moreover, the prepared device can be used as an optical data receiver for UV optical communication. With compatibility and integrability to Si-based optoelectronics platforms, the devices are appealing for sensing, imaging and communications. Higher large-scale on-chip integrated photodetector array on a Si wafer are proposed, which consist of 21x21 GaN p-n homojunction active pixels. The GaN subunit has significant photovoltaic performance at 0 V, and GaN units have small relative deviations. The proof of concept for GaN imaging and communication capabilities has been completed. image