Hydrogen passivation of AlxGa1-xAs/GaAs studied by surface photovoltage spectroscopy

We study the effect of hydrogen passivation on Al1-xGal-xAs grown by liquid -phase epitaxy (LPE) on semi-insulating GaAs. Using surface photovoltage (S PV) spectroscopy and Hall measurements we investigate the effect of hydroge nation on AlxGa1-xAs epilayers with electron concentrations in the range 10 (16)-10(17)cm(-3). We measure the minority carrier diffusion length in the as-grown AlxGa1-xAs epilayers to be in the range 0.1-0.8 mu m and to increa se significantly upon hydrogenation. Hydrogen passivation of interface stat es at the heterojunction is demonstrated for epilayers with low carrier con centration. We apply the result from the SPV measurements to speculate on t he band bending at the heterojunction. (C) 1999 Elsevier Science B.V. All r ights reserved.