High-speed InP/InGaAs heterojunction phototransistor for millimetre-wave fibre radio communications

InP photodetectors for millimeter-wave applications

“…The first experimental demonstration of InP heterojunction phototransistor able to operate in the millimeter wave frequency range is, to our knowledge, due to David Wake 12 with a two terminal HPT with no base contact. More recent experimental and theoretical results confirmed the capabilities of InP HPT for millimeter wave applications, either vertical 13 or edge illuminated 14 . An heterojunction phototransistor can be considered as an heterojunction bipolar transistor (HBT) for which the basecollector junction is used as a photodiode.…”

InP/InGaAS Symmetric Gain Optoelectronic Mixers

“…A base bias can be provided, either optically or by an electrical contact [6]. The base composition can be graded to establish an electric field which enhances electron transport [7,8].It was demonstrated that symmetric-area heterojunction phototransistors have a larger bandwidth than asymmetric area HPTs [9]. It should be noted that while Milano et al predicted a rather pessimistic bandwidth, improvements in material growth, device design and fabrication techniques have improved the maximum bandwidth of HPTs to the tens of GHz range [10,11].…”

Ultrahigh Responsivity-Bandwidth Product in a Compact InP Nanopillar Phototransistor Directly Grown on Silicon

“…This could also be viewed as an intimate integration of the first amplifier stage with the photodetector, thus eliminating the wire capacitance altogether. Several approaches have been attempted, including Si/Ge and In(Al,Ga)As avalanche photodiodes 17 18 19 20 , field effect phototransistors 21 22 and bipolar junction phototransistors 10 23 24 25 26 27 28 29 30 31 . Avalanche photodiodes with high gain-bandwidth product have been demonstrated 17 18 19 .…”

“…This allows a higher gain-bandwidth product to be reached at the same DC collector current 43 . While promising gain-bandwidth products have been achieved using III-V based phototransistors with highly scaled geometries, the small size leads to deficient photon absorption 23 26 27 28 30 . Additionally, the high lattice mismatch of InP and GaAs with silicon leads to defective material unsuitable for devices.…”