【Device Papers】High-sensitivity x-ray detection of stacked A4 sheets using Ga₂O₃ Schottky barrier diodes: Toward low-dose imaging and material discrimination

      Researchers from the Korea Aerospace University have published a dissertation titled "High-sensitivity x-ray detection of stacked A4 sheets using Ga₂O₃ Schottky barrier diodes: Toward low-dose imaging and material discrimination" in Applied Physics Letters.

Abstract

      This study investigates the performance of a β-Ga₂O₃-based x-ray detector in distinguishing the number of stacked A4 sheets under x-ray illumination. The detector is fabricated using an 11-μm thick Si-doped n-type β-Ga₂O₃ epitaxial layer on an Sn-doped β-Ga₂O₃ substrate with Schottky and Ohmic contacts. The device demonstrates well-defined Schottky diode characteristics with an on/off current ratio exceeding 10⁶ and a low leakage current. X-ray sensitivity measurements reveal a significant increase in photocurrent under reverse bias with a maximum sensitivity of 820 μC·Gy_air⁻¹·cm⁻² at −10 V. The attenuation current efficiency is analyzed using the Beer–Lambert law, demonstrating an exponential relationship between cellulose thickness and current reduction. Furthermore, a temporal response analysis reveals rapid rise and fall times (0.15 and 0.13 s, respectively) that remain consistent across varying attenuation levels, indicating stable and repeatable operation. The device detects up to seven stacked A4 sheets, highlighting its potential for document authentication, material inspection, and radiation sensing. The results suggest that Ga₂O₃-based x-ray detectors can serve as a promising solution for high-sensitivity, low-dose x-ray applications.

DOI：

https://doi.org/10.1063/5.0283387