14:00 〜 14:15
▲ [19p-Z08-4] Giant Responsivity in Metasurface Quantum Well Infrared Photodetectors at High Bias
キーワード：metasurface, quantum well, infrared photodetector
Metasurface quantum well infrared photodetectors are highly tunable and sensitive infrared photodetectors integrating quantum well infrared photodetectors (QWIPs) and metal-dielectric-metal plasmon cavities. The resonances of the QWIP and cavity can be fully controlled, enabling responsivities up to 4 A/W at 7.06 μm in detectors using single-quantum-well QWIP layers and unetched square cavities.
Here, we report unique behavior in metasurface QWIPs with unetched square cavities and a three-quantum-well QWIP layer. Compared to single-quantum-well metasurface QWIPs, maximum responsivity at low bias voltages is reduced, ~2 A/W at 7.06 μm for both negative and positive applied bias (-0.8V or +0.9V). However at negative bias, after initially decreasing beyond ~1 V of applied bias, responsivity dramatically increases above -2.0V (~100 kV/cm). A peak responsivity Rpeak of 14.6 A/W is reached at 7.06 μm and -2.7 V bias (~135 kV/cm), corresponding to a 257% quantum efficiency and suggesting that the giant Rpeak arises from avalanche carrier multiplication. Rpeak at -2.7 V is six times larger than the corresponding Rpeak at the low bias peak for the same detector, and more than three times larger than Rpeak for metasurface QWIPs using a single quantum well. Due to increased dark current and noise—also characteristic of avalanche multiplication—detectivity at -2.7 V is reduced to 5.4 108 cm Hz1/2/W compared to detectivity at low bias (2.4 1010 cm Hz1/2/W at -0.9 V).
Here, we report unique behavior in metasurface QWIPs with unetched square cavities and a three-quantum-well QWIP layer. Compared to single-quantum-well metasurface QWIPs, maximum responsivity at low bias voltages is reduced, ~2 A/W at 7.06 μm for both negative and positive applied bias (-0.8V or +0.9V). However at negative bias, after initially decreasing beyond ~1 V of applied bias, responsivity dramatically increases above -2.0V (~100 kV/cm). A peak responsivity Rpeak of 14.6 A/W is reached at 7.06 μm and -2.7 V bias (~135 kV/cm), corresponding to a 257% quantum efficiency and suggesting that the giant Rpeak arises from avalanche carrier multiplication. Rpeak at -2.7 V is six times larger than the corresponding Rpeak at the low bias peak for the same detector, and more than three times larger than Rpeak for metasurface QWIPs using a single quantum well. Due to increased dark current and noise—also characteristic of avalanche multiplication—detectivity at -2.7 V is reduced to 5.4 108 cm Hz1/2/W compared to detectivity at low bias (2.4 1010 cm Hz1/2/W at -0.9 V).