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

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·Gyair−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.