Non-monotonic effect of growth pressure on the responsivity of AlGaN ultraviolet Schottky detectors

Three AlGaN-based Schottky detector samples grown with varying pressure conditions are prepared and their responsivity is investigated. It is found that the responsivity of the three samples first increases and then decreases with the increase of pressure. In addition, the vacancy defect concentration increases and carbon impurities concentration decreases when the reactor pressure increases from 100 mbar to 200 mbar during the i-AlGaN layer growth. It is assumed that carbon impurities and vacancy defects play a negative role in detector’s performance, which increase the recombination of photogenerated carriers and reduce detector responsivity. The relationship between growth pressure and detector responsivity is not linear. It is necessary to select a suitable growth pressure to improve the performance of AlGaN detectors.