Vapor grown indium gallium arsenide (InGaAs) detectors are normally1 fabricated with an indium phosphide (InP) cap layer which passivates the InGaAs and is transparent to light of a wavelength beyond 920 nm. Shorter wavelengths are strongly absorbed by this cap, and only ~5% of visible light is transmitted through a 2-μm thick InP cap. Previous work2 with 0.1- and 0.5-mm diam mesa detectors has shown that the visible response of these devices can be improved by utilizing thin (<1-μm) InP caps which allow significant transmission of visible light. The present work3 demonstrates that vapor grown planar InGaAs detectors with 2-, 3-, and 5-mm diam active areas can be made with quantum efficiencies as high as 38% at 400 nm, 42% at 600 nm, 50% at 800 nm, and 70% at 1300 and 1550 nm. Such detectors are unique and for the first time provide a usable large area high QE single-element detector for the 400-1700-nm spectral range, suitable as a traceable laboratory standard.
© 1988 Optical Society of AmericaPDF Article