2:00 PM - 2:15 PM
▲ [19p-Z08-4] Giant Responsivity in Metasurface Quantum Well Infrared Photodetectors at High Bias
Keywords: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).