Self-powered proton detectors based on GaN core–shell p–n microwires

Abstract

Self-powered particle detectors have the potential to offer exceptional flexibility and compactness in applications where size limits and low power consumption are key requisites. Here, we report on the fabrication and characterization of radiation sensors based on GaN core/shell p–n junction microwires working without externally applied bias. With their small size, high resistance to radiation, and high crystalline quality, GaN microwires constitute highly interesting building blocks for radiation-hard devices. Through microfabrication steps, single-wire devices were processed that show a leakage current as low as 1 pA in reverse bias. Irradiation with both UV light and 2 MeV protons results in photo/ionocurrent signals several orders of magnitude above the dark current and response times below 30 ms. The sensor also showed a good resistance to radiation. Although we observed a small increase in the leakage current after a prolonged proton irradiation, the measured transient ionocurrent signal remains stable during irradiation with a total proton fluence of at least 1×1016 protons/cm2.

Charge Collection Efficiency of Single GaN Core–Shell Wires Assessed by High-Precision Ion-Beam-Induced Charge Measurements

“…The I – V curve demonstrates the rectifying nature of the device, and a leakage current of around 1 nA at a reverse bias of −2 V is measured. Previous photoconductivity measurements carried out by us on detectors fabricated with similar wires through the same process also show the p–n junction signature of the device, demonstrating that despite the low acceptor concentration p-type conductivity and a rectifying p–n junction is achieved …”

“…Here, we can see that the CCE does not vary much when applying a positive or a zero bias and that it increases significantly when applying a reverse bias. The detector irradiated with the 750 keV ions shows a CCE of 11% at a bias of 0 V, evidencing the self-powering property of the detector, and when applying −2 V to the detector, it increases to around 25%. The same analysis was carried out for the detector irradiated with 1 MeV Si ions; in this case, the average CCE goes from 7.3% at zero bias, to 21.4% at −2 V and to 24.1% at a reverse bias of −4 V. It is curious to see that, when increasing the reverse bias beyond −2 V, the increase rate of the CCE becomes smaller.…”

Radiation-Tolerant Proton Detector Based on the MAPbBr3 Single Crystal

“…Notably, a high sensitivity of (2.19 ± 0.03) × 10 –18 C cm 2 p –1 was obtained at a bias of −10 V, which corresponded to an electric field of 0.01 V μm –1 . Particularly, this applied bias was fairly low as compared to other types of proton detectors, and such a low operation voltage is desirable for the applications in energy-sparse environments, such as in space applications. − …”

Damage in InGaN/GaN bilayers upon Xe and Pb swift heavy ion irradiation

“…[18][19][20][21] Nonetheless, the compounds are also promising materials for power electronics, sensors, or photodetectors. 22,23 Moreover, due to high resistance to radiation damage, they are expected to work at high temperatures and to resist harsh environments with exposure to irradiation, e.g., in space applications. 24 Although structural damage formation in GaN upon ion bombardment has been thoroughly examined during the last decades, 3,[24][25][26][27][28][29] the irradiation effects in InGaN remain barely investigated and understood, especially those caused by strongly ionizing radiation.…”

“…18–21 Nonetheless, the compounds are also promising materials for power electronics, sensors, or photodetectors. 22,23 Moreover, due to high resistance to radiation damage, they are expected to work at high temperatures and to resist harsh environments with exposure to irradiation, e.g. , in space applications.…”