Low‐temperature‐grown gallium arsenide photoconductors with subpicosecond carrier lifetime and photoresponse reaching 25 mA/W under 1550 nm CW excitation

Abstract

The authors show in this Letter that photoconductors based on GaAs grown at low temperatures can exhibit photoresponses as high as 25 mA/W under continuous-wave 1550-nm-wavelength illumination. It is achieved by using an optical Fabry-Pérot cavity in order to improve the external quantum efficiency and by decreasing the post-growth annealing temperature down-to 450°C.

Development of a Millimeter-Long Travelling Wave THz Photomixer

“…In this study, a genuine travelling-wave behavior has been demonstrated as a first step toward photomixers with unprecedented performance. Recent promising optimization of the absorption of 1550-nm light in LT-GaAs [48] give us hope that this concept could be also promising to develop TW photomixers pumped by lowcost and powerful 1550-nm fiber lasers and amplifiers. A1.…”

Terahertz Detection Using Enhanced Two‐Step Absorption in Photoconductive Metasurfaces Gated at λ = 1.55 µm

“…However, the extinction coefficient for subbandgap absorption in LT‐GaAs is not well known and it varies with the material growth conditions and annealing temperature. [ 31 ] Furthermore, due to the two‐step absorption process, the material absorption in LT‐GaAs at this wavelength increases non‐linearly with the incident power. [ 18 ] We therefore make an initial estimate of κ = 0.01 using previous studies that report ≈5% absorption of a 500 nm thick LT‐GaAs layer pumped with 80 fs pulses at 1.57 µm with an average incident power of 50 mW.…”