High-speed picosecond pulse response GaNAsSb p-i-n photodetectors grown by rf plasma-assisted nitrogen molecular beam epitaxy

Abstract

The authors report on picosecond pulse response GaNAsSb∕GaAs p-i-n photodetectors grown by molecular beam epitaxy in conjunction with a rf plasma-assisted nitrogen source. The 2μm thick GaNAsSb photoabsorption layer contains 3.3% of N and 8% of Sb resulting in a dc photoresponse up to 1380nm wavelength. Dark current densities at 0 and −5V are 1.6×10−5 and 13A∕cm2, respectively. The GaNAsSb photodiodes exhibit a record pulse response width of only 40.5ps (full width at half maximum) corresponding to a 4.5GHz bandwidth.

Molecular beam epitaxy growth of bulk GaNAsSb on Ge/graded-SiGe/Si substrate

“…The acceptance criterion for the transfer of GaNAsSb growth process to SVS is smooth surface morphology (o0.4 nm AFM surface roughness). These GaNAsSb layer was grown at 400 1C, in this study, to promote kinetic incorporation of N, and further considerations of bulk GaNAsSb grown on GaAs are already reported elsewhere [11]. The epitaxy growth conditions are identical with the exception of GaAs growth temperature of 650, 610, and 580 1C, respectively (see Fig.…”

“…However, it is known that the competition between the group-V elements of N, As, and Sb presented an enormous challenge for a successful growth of bulk GaNAsSb. Hence, the growth optimization of bulk GaNAsSb with at least a thickness of 500 nm was conducted on GaAs substrate in a separate study [11]. The acceptance criterion for the transfer of GaNAsSb growth process to SVS is smooth surface morphology (o0.4 nm AFM surface roughness).…”

“…Success was also limited by the short minority carrier lifetime in bulk GaInNAs materials due to the presence of deep level traps [8]. In order to avoid the detrimental effect of In-N clustering and to embrace the beneficial effect of Sb in possibly reducing N migration, and hence suppressing the formation of N-complex, the GaNAsSb material was investigated [8][9][10][11]. To the best of our knowledge, this is the first nitrogenplasma-assisted molecular beam epitaxy (MBE) growth demonstration of GaNAsSb on the Ge/graded-SiGe/Si substrate.…”

Molecular beam epitaxy grown GaNAsSb 1eV photovoltaic cell

“…GaNAsSb was firstly proposed by Ungaro et al [7] as a potential GaAs-based small bandgap (o1.4 eV) material. Recently, GaNAsSb has been demonstrated as a promising material for near infrared photodetectors [8][9][10] and photoconductive switches [11] due to its capability to achieve small energy bandgap, E g (0.8-1.0 eV), and to be lattice-matched to a GaAs substrate. These characteristics enable GaNAsSb to be a potential active material for the 1 eV photovoltaic junction.…”

DC Performance of High-Quantum-Efficiency 1.3-$\mu \hbox{m}$ GaNAsSb/GaAs Waveguide Photodetector

“…At a reverse bias voltage of 5 V, the measured dark current density is 0.54 A/cm 2 . This value is more than one order smaller than the value of 13 A/cm 2 previously reported in our p-i-n photodetectors [4], which is mainly attributed to the thinner GaNAsSb layer (0.4 μm versus 2 μm) and reduced growth temperature (350 • C versus 440 • C) which reduces the overall trap concentration [5], [6]. The device exhibited a turn-on voltage of 0.72 V at I = 1.09 mA and a reverse breakdown voltage of −16.6 V at I = 1.06 mA.…”