1. Improved performance of ultraviolet AlGaN/GaN npn HPTs by a thin lightly-doped n-AlGaN insertion layer.
- Author
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Tang, Shaoji, Zhang, Lingxia, Wu, Hualong, Liu, Changshan, and Jiang, Hao
- Subjects
SPACE charge ,CONDUCTION bands ,SPECTRAL sensitivity ,PHOTOTRANSISTORS ,HETEROJUNCTIONS ,ELECTRIC fields ,DOPING agents (Chemistry) ,INDIUM gallium nitride - Abstract
We reported the improved performance of ultraviolet two-terminal Al
0.1 GaN/GaN npn heterojunction phototransistors with a 10-nm-thick low-doped n-type Al0.1 GaN insertion layer between emitter and base. Optical current gain at 2 V bias was increased from 6.6 × 103 to 9.8 × 104 by inserting the thin undoped layer. Spectral response measurements showed a high ultraviolet to visible (350 nm/400 nm) rejection ratio of 6.7 × 104 under 2 V bias, while that of the control sample without the insertion layer is 2.4 × 103 . Simulation analysis reveals that the conduction band notch at the interface of the base-emitter (B-E) heterojunction is lowered by the insertion layer, leading to a weakened electric field and a narrowed space-charge region at the interface. This effect can reduce the recombination in the B-E heterojunction and contribute to the improved gain performance of the phototransistor. [ABSTRACT FROM AUTHOR]- Published
- 2019
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