p-n Heterojunctions of Emergent Wide band gap Oxides for self-powered UVC sensing – HEWOX
Uncontrolled fires are estimated to contribute as much to carbon gas emissions as all of commercial transport and must thus be a critical challenge for the EU Green Deal objective of no carbon gas emissions by 2050. A key problem is that these fires are often not detected in time to limit the damage because most commercial fire/smoke detectors usually do not go off until it is too late to intervene and quell the conflagration before it takes hold. Remote optical sensing should be a big part of the solution. Although infrared (IR) sensors are the conventional solution for heat detection, they are not ideal for remote optical fire detection because they are subject to multiple confounding signals.
Ultraviolet (UV) photodetectors (PD) are emerging for a whole range of applications including flame/spark detection, chemical/biological-agent detection, missile early warning systems, missile guidance, muzzle flash detection, military counter-measures, environmental monitoring, UV sterilization monitoring, non-line-of-sight communications and UV space astronomy . To minimize false alarms and background clutter, many of these devices respond uniquely in the UVC portion of the spectrum (< 290 nm) and are, thus, solar blind (SB). Most current PD employ photomultipliers (PMs). These are based on vacuum tubes, which are bulky, fragile (mechanically and electrically) expensive and require high operating voltages. Solid-state SBPDs, based on semiconductors, are much more robust than PMs and offer both size and cost advantages. They also have the potential for higher quantum efficiency, intrinsic spectral range selectivity, extended lifetimes, lower noise and lower power requirements. Several different kinds of semiconductor-based UVC PD have been developed. Silicon photodiodes have long been used for UV detection. Although they work well, their bandgap is relatively low, so they respond to the visible spectrum as well UV signals and require optical filters in order to be either visible or solar blind. A class of materials called “wide bandgap (WBG)” semiconductors is naturally visible blind, however.
For this reason, there is a need for ultraviolet C band (UVC) flame sensors, which are not subject to such false positives because their photoresponse is solar blind.
3 European partners, Nanovation (SME, France), UCM (University Complutense of Madrid, Spain), and TUD (Dresden Center for Computational Materials Science, Germany) are joining their skills to develop this sensor with new semiconductor materials as well as new processes within the project HEWOX.
HEWOX will explore and contrast the advantages of developing of Ga2O3/NiO heterojunctions (in both thin film and nanomaterial form) for use as self-powered remote fire/flame sensors. This approach reinforces the innovative character of the project due to merging of UVC sensing and autonomous operation into a functional materials platform, by employing emerging ultra-wide band gap oxides.
Monsieur David Rogers (Nanovation SARL)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
Nano Nanovation SARL
Help of the ANR 224,991 euros
Beginning and duration of the scientific project: March 2023 - 36 Months