Optical properties of porous GaAs

The optical properties of porous GaAs formed electrochemically on n- and p-type GaAs in HCl electrolyte are reported. The porous structure comprises GaAs crystallites ranging in size from micrometers to nanometers and under certain chemical conditions other transparent crystallites of As 2 O 3 and Ga 2 O 3 form. Photoluminescence (PL) measurements at 295 K reveal an “infrared” PL at ∼840 nm and a “green” PL at ∼ 540 nm, which could easily be seen by the naked eye in some samples. The infrared and green PL peak wavelength and intensity varied from sample to sample consistent with an assignment to quantum confinement effects in GaAs micro- and nanocrystallites, respectively.