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P1-29 ᐅ

FORMATION AND INVESTIGATION OF GAN SENSORS FOR RECORDING OF IONIZING RADIATION

Jonas Seilius1, Vytautas Rumbauskas1, Tomas Čeponis1, Rokas Dobužinskas2

1 Institute of Photonics and Nanotechnology, Vilnius University, Saulėtekio av. 3, LT-10257, Vilnius, Lithuania

2 Institute of Chemical Physics, Vilnius University, Saulėtekio av. 3, LT-10257, Vilnius, Lithuania

[email protected]

The rapid development of technology requires reliable and high-quality sensors capable of operating in extreme conditions, such as exposure to ionizing radiation. This radiation can originate from natural sources like cosmic rays, radionuclides in the Earth’s crust, or radon, as well as artificial sources such as nuclear power plants, medical equipment, and scientific facilities.

Due to its high radiation resistance, gallium nitride (GaN) is being extensively studied for ionizing radiation detection. GaN exhibits superior properties, such as a wide bandgap, high thermal stability, and excellent radiation hardness. These qualities make it a promising candidate for developing sensors in particle physics, astronomy, and nuclear science [1,2].

During investigation, the tube voltage (20kV to 60kV) and current were varied.The study involved two types of samples. The first group consisted of three GaN LED structures (811, 807, 886) grown by Metal-Organic Chemical Vapor Deposition (MOCVD) at the Vilnius University Nitride Technology Group. The second group included two commercial Schottky photodiodes: GUV B (AlGaN-based) and GUV C (AlN-based). One of them (GUV B) showed no signal. The recorded values were grouped by tube voltage and plotted on a logarithmic scale.

Figure 1
Fig. 1. Short-circuit current dependence on X-ray tube current at 60 kV voltage
The sensor response to varying X-ray intensity shows that GaN LED 807 provided the highest signal, which is linear on a double logarithmic scale. In contrast, GUV C data points were more scattered due to its weak and noisy signal. The stronger response of GaN LED 807 may result from a thinner pGaN layer, reducing charge carrier recombination. As expected, Schottky diodes were less sensitive to X-rays, and no signal was detected from GUV B due to damaged electrical contacts.

GaN LED 807 showed the highest X-ray sensitivity, with a linear response on a double logarithmic scale, suggesting reduced carrier recombination due to its thinner p-GaN layer. GUV C’s broader signal dispersion indicates higher noise and lower sensitivity, while the absence of response from GUV B is attributed to electrical contact failure.

[1] Sandupatla, A., Arulkumaran, S., Ing, N. G., Nitta, S., Kennedy, J., & Amano, H. Vertical GaN-on-GaN Schottky diodes as α-particle radiation sensors. Micromachines, 11(5), 519. (2020).

[2] Geng, X., Xia, X., Liu, J., Cui, X., Sun, Z., Huang, H., ... & Liang, H.. Charge transport mechanism of self-powered GaN pin α-particle detector. Superlattices and Microstructures, 143, 106563. (2020).