Impact of Gamma Radiation on Fabricated Aluminum Gallium Nitride/Gallium Nitride Test Structures for Radiation-Hard Electronics

In the harsh environment of space, deep within nuclear facilities, or near particle accelerators, standard electronic components often fail. The invisible rain of high-energy particles and rays that permeate these places can scramble the delicate pathways inside a computer chip, causing it to stop working or behave unpredictably. To survive such conditions, engineers look to a special class of materials known as wide-bandgap semiconductors. Among these, a combination of aluminum gallium nitride and gallium nitride has emerged as a particularly strong candidate. These materials are naturally tough, capable of handling high heat and high voltage better than the silicon found in most everyday electronics. Because of this resilience, scientists are eager to understand exactly how these materials react when bombarded by radiation, hoping to build electronics that can operate reliably where others would perish.

A researcher at the Indian Institute of Technology Jodhpur set out to test this resilience directly. They took a wafer of aluminum gallium nitride and gallium nitride and carefully cut it into small pieces to create simple electronic devices. Using a process similar to printing a circuit board, they patterned the material and added metal contacts made of aluminum, chromium, and gold to form two-terminal devices. After heating the devices to ensure the metal connected well with the semiconductor, the team measured how electricity flowed through them. They then subjected these devices to gamma radiation, a powerful form of energy emitted by a cobalt source, at three specific levels of intensity: 100 cGy, 500 cGy, and 1000 cGy. After each exposure, they measured the flow of electricity again to see how the radiation had changed the device's behavior.

The results revealed a clear and significant impact from the radiation. Before any exposure, the devices allowed a steady flow of current, measuring 0.01697 amperes when a forward voltage was applied. This initial reading served as the baseline for a healthy, functioning device. However, after the first exposure to 100 cGy of gamma radiation, the current dropped dramatically. The flow fell to just 0.000652 amperes, a reduction of nearly 96 percent. This massive drop suggested that the radiation had created defects and trapped charges within the material, effectively blocking the path for electrons to move. The device was still working, but it was struggling significantly.

When the dose was increased to 500 cGy, the behavior became more complex. The current did not continue to drop in a straight line; instead, it rose slightly to 0.009103 amperes. While this was still much lower than the original, unexposed value, the partial recovery indicated that different forces were at play. The researcher noted that while radiation continued to create damage, other processes, such as the redistribution of electrical charges or the healing of some defects, might have been occurring simultaneously. This non-linear response showed that the material's reaction to radiation is not a simple, one-way degradation but a dynamic interaction between damage and recovery.

At the highest tested dose of 1000 cGy, the current decreased again, settling at 0.007126 amperes. This final value was lower than the 500 cGy reading but higher than the 100 cGy reading, confirming that the device remained electrically functional even after significant exposure. The researcher concluded that the radiation had indeed introduced defects and trapped charges that scattered the moving electrons, reducing the overall flow. However, the fact that the devices did not fail completely suggests that aluminum gallium nitride and gallium nitride structures possess a natural ability to withstand low-to-moderate doses of gamma radiation.

These findings offer valuable insights for the future of electronics in extreme environments. Because the devices showed a measurable and consistent change in their electrical properties based on the radiation dose, they could potentially be used as sensors to measure radiation levels. Furthermore, the ability of these structures to remain operational after exposure supports their use in satellites, deep space probes, and nuclear control systems where reliability is paramount. The study confirms that while radiation does degrade performance, it does not immediately destroy these advanced materials, paving the way for more robust electronic systems designed to operate in the most challenging corners of our universe.