VISIBLE PHOTOLUMINESCENCE FROM POROUS GAAS

Porous GaAs was formed electrochemically on n-type GaAs(100) in a 0.1 M HCl electrolyte. Scanning electron microscopy revealed feature sizes of the porous structure in the micrometer to nanometer range. The opt ical properties of the porous material were characterized by photolumi nescence (PL) measurements at 295 K. Compared with untreated GaAs, a s hift down of the ''infrared'' PL maximum to similar to 840 nm can be o bserved. An additional ''green'' PL peak occurs at similar to 540 nm t hat in some samples is readily visible to the naked eye. The ''green'' and the ''infrared'' PL are ascribed to quantum confinement effects i n GaAs nano- and microcrystallites, respectively. (C) 1996 American In stitute of Physics.