Electrically tunable homojunctions based on ambipolar two-dimensional materials have attracted widespread attention in the field of intelligent vision.These devices exhibit inherent switchable positive and negative ph...Electrically tunable homojunctions based on ambipolar two-dimensional materials have attracted widespread attention in the field of intelligent vision.These devices exhibit inherent switchable positive and negative photovoltaic properties that effectively mimic the behavior of human retinal cells.However,the photovoltaic responsivity of most electrically tunable homojunctions remains significantly low due to the weak light absorption,making it challenging to meet the application requirements for high-sensitivity target detection in the field of intelligent vision.Here,we propose a gate-tunable photodiode based on two-dimensional ambipolar WSe_(2)with an asymmetric gate electrode,achieving high photovoltaic responsivity.By adjusting the gate voltage and keeping bias voltage zero,we can dynamically realize reconfigurable n-–p and n-–n homojunction states,as well as gate-tunable photovoltaic response characteristics that range from positive to negative.The maximum photovoltaic responsivity of the electrically tunable WSe_(2)homojunction is approximately 0.4 A/W,which is significantly larger than the previously reported value~0.1 A/W in homojunction devices.In addition,the responsivity can be further enhanced to approximately 1.0 A/W when the n-–p photodiode operates in reverse bias mode,enabling highsensitivity detection of targets.Our work paves the way for developing gate-tunable photodiodes with high photovoltaic responsivity and advancing high-performance intelligent vision technology.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62375131,62204119,62122036,and 62304104)the Natural Science Foundation of Jiangsu Province(Grant No.BK20220947)the Funding of NJUST(Grant No.TSXK2022D008)。
文摘Electrically tunable homojunctions based on ambipolar two-dimensional materials have attracted widespread attention in the field of intelligent vision.These devices exhibit inherent switchable positive and negative photovoltaic properties that effectively mimic the behavior of human retinal cells.However,the photovoltaic responsivity of most electrically tunable homojunctions remains significantly low due to the weak light absorption,making it challenging to meet the application requirements for high-sensitivity target detection in the field of intelligent vision.Here,we propose a gate-tunable photodiode based on two-dimensional ambipolar WSe_(2)with an asymmetric gate electrode,achieving high photovoltaic responsivity.By adjusting the gate voltage and keeping bias voltage zero,we can dynamically realize reconfigurable n-–p and n-–n homojunction states,as well as gate-tunable photovoltaic response characteristics that range from positive to negative.The maximum photovoltaic responsivity of the electrically tunable WSe_(2)homojunction is approximately 0.4 A/W,which is significantly larger than the previously reported value~0.1 A/W in homojunction devices.In addition,the responsivity can be further enhanced to approximately 1.0 A/W when the n-–p photodiode operates in reverse bias mode,enabling highsensitivity detection of targets.Our work paves the way for developing gate-tunable photodiodes with high photovoltaic responsivity and advancing high-performance intelligent vision technology.
