A novel RCE (Resonant-Cavity- Enhanced) HMSM (Heterostructure Metal-Semiconductor-Metal) photodetector with AlGaAs distributed Bragg reflector is analyzed. The effect of the two dimensional electron gas (2DEG) in the GaAs absorption layer has been evaluated by comparing two samples, the first with a delta doped sheet in the upper AlGaAs layer, and the second with undoped AlGaAs. The I-V curve shows that there is a very low dark current (around 10 picoamps at high bias) and a value of 20 microamps at high bias voltage in DC photocurrent, under 497 μW optical power laser illumination. C-V measurements highlight very low capacitance values, in agreement with the calculated geometrical ones. The photocurrent spectrum shows a clear peak at 850 nm wavelenght with full width at half maximum (FWHM) of around 30 nm, while time response measurement gives a 3 dB bandwidth of about 34 GHz. Combination of very low dark current and capacitance, fast response, wavelength selectivity, and compatibility with high electron mobility transistors makes this device especially suitable for short haul communications purposes.
Static and Dynamic Characterization of High Speed HMSM Photodetecors for Short Haul Communications
CATALDO, Andrea Maria;
2002-01-01
Abstract
A novel RCE (Resonant-Cavity- Enhanced) HMSM (Heterostructure Metal-Semiconductor-Metal) photodetector with AlGaAs distributed Bragg reflector is analyzed. The effect of the two dimensional electron gas (2DEG) in the GaAs absorption layer has been evaluated by comparing two samples, the first with a delta doped sheet in the upper AlGaAs layer, and the second with undoped AlGaAs. The I-V curve shows that there is a very low dark current (around 10 picoamps at high bias) and a value of 20 microamps at high bias voltage in DC photocurrent, under 497 μW optical power laser illumination. C-V measurements highlight very low capacitance values, in agreement with the calculated geometrical ones. The photocurrent spectrum shows a clear peak at 850 nm wavelenght with full width at half maximum (FWHM) of around 30 nm, while time response measurement gives a 3 dB bandwidth of about 34 GHz. Combination of very low dark current and capacitance, fast response, wavelength selectivity, and compatibility with high electron mobility transistors makes this device especially suitable for short haul communications purposes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
