The photoconductive response of AlGaN based UV detectors to 193 nm excimer laser radiation is presented. Two devices have been tested: a metal-semiconductor-metal MSM planar structure and a Schottky diode. The transient response of the MSM device closely follows the laser pulses, with a photoconductive decay time constant shorter than 3 ns. Conversely, the Schottky diode shows a slower photoconductive rise and decay kinetics due to the material series resistance coupled with the junction capacitance. Moreover, a longer time constant tail is also evident in this case with a characteristic time of about 40 ns, due to the presence of trap states localized at 0.2–0.3 eV from the band edge. The detection dynamics has been evaluated by changing the beam energy density between 210−5 and 0.2 mJ/mm2. The signal increases linearly in the case of the MSM device up to 0.001 mJ/mm2, whereas, for a further intensity rise, the response shows a sublinear behavior. On the contrary, the Schottky diode showed a linear trend inside the reduced 210−3–1.5 10−2 mJ/mm2 range.
G., M., Conte, G., J. L., R., A., D., J. Y., D. (2006). Deep ultraviolet detection dynamics of AlGaN based devices. APPLIED PHYSICS LETTERS, 89, 223513-223515 [10.1063/1.2397019].
Deep ultraviolet detection dynamics of AlGaN based devices
CONTE, Gennaro;
2006-01-01
Abstract
The photoconductive response of AlGaN based UV detectors to 193 nm excimer laser radiation is presented. Two devices have been tested: a metal-semiconductor-metal MSM planar structure and a Schottky diode. The transient response of the MSM device closely follows the laser pulses, with a photoconductive decay time constant shorter than 3 ns. Conversely, the Schottky diode shows a slower photoconductive rise and decay kinetics due to the material series resistance coupled with the junction capacitance. Moreover, a longer time constant tail is also evident in this case with a characteristic time of about 40 ns, due to the presence of trap states localized at 0.2–0.3 eV from the band edge. The detection dynamics has been evaluated by changing the beam energy density between 210−5 and 0.2 mJ/mm2. The signal increases linearly in the case of the MSM device up to 0.001 mJ/mm2, whereas, for a further intensity rise, the response shows a sublinear behavior. On the contrary, the Schottky diode showed a linear trend inside the reduced 210−3–1.5 10−2 mJ/mm2 range.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
