AlGaN solar-blind phototransistor capable of directly detecting sub-fW signals:self-depletion and photorecovery of full-channel 2DEG enabled by a quasi-pseudomorphic structure  

作　　者：JIABING LU ZESHENG LV HAO JIANG 

机构地区：[1]School of Electronics and Information Technology,Sun Yat-sen University,Guangzhou 510006,China [2]State Key Laboratory of Optoelectronic Materials and Technologies,Sun Yat-sen University,Guangzhou 510006,China [3]Guangdong Engineering Technology R&D Center of Compound Semiconductors and Devices,Sun Yat-sen University,Guangzhou 510006,China

出　　处：《Photonics Research》2023年第7期1217-1226,共10页光子学研究（英文版）

基　　金：National Key Research and Development Program of China (2022YFB3604904);Key Realm Research and Development Program of Guangzhou (202103030002)。

摘　　要：Heterojunction field-effect phototransistors using two-dimensional electron gas(2DEG)for carrier transport have great potential in photodetection owing to its large internal gain.A vital factor in this device architecture is the depletion and recovery of the 2DEG under darkness and illumination.This is usually achieved by adding an external gate,which not only increases the complexity of the fabrication and the electrical connection but also has difficulty ensuring low dark current(I_(dark)).Herein,a quasi-pseudomorphic AlGaN heterostructure is proposed to realize the self-depletion and photorecovery of the 2DEG,in which both the barrier and the channel layers are compressively strained,making the piezoelectric and spontaneous polarization reverse,thus depleting the 2DEG and tilting the entire barrier and channel band to form two built-in photogates.The fabricated solar-blind phototransistors exhibit a very low I_(dark)below 7.1×10^(-10)mA∕mm,a superhigh responsivity(R)of 2.9×10^(9)A∕W,a record high detectivity(D^(*))of 4.5×10^(21)Jones,and an ultrafast response speed at the nanosecond level.The high performance is attributed to the efficient depletion and recovery of the full 2DEG channel by the two photogates,enabling direct detection of the sub-fW signal.This work provides a simple,effective,and easily integrated architecture for carrier control and supersensitive photodetection based on polarization semiconductors.

关 键 词：CHANNEL polarization ALGAN 

分 类 号：TN386[电子电信—物理电子学]