Low-noise In0.53Ga0.47As:Fe photoconductive detectors for optical communication

Photoconductive detectors were fabricated on In
0.53
- Ga
0.47
As/InP made high-resistive by doping with elemental Fe. A mobility of ∼ 6000 cm
²
/V . s and a net electron concentration of (2-5) × 10
¹²
cm
^-3
were measured in layers on which the devices were fabricated. Photoconductive gains of 5-10 were measured with CW and pulsed excitation. The calculation response time to 300-ps pulsed excitation is ∼ 100 ps and can be improved with reduced channel spacings. Typical dark currents in the devices are of the order of 50 µ A at room temperature. The noise power into a 50-Ω load measured at 82°C is -108.9 dBm. This is the lowest value measured in photoconductive detectors made with III-V In
0.53
Ga
0.47
As.