  The diffusion length of minority carriers L p,n is an important
characterisation parameter in semiconductor materials and is of particular
interest when constructing devices such as solar cells (Hovel 1975), double
hetero junction lasers (Casey and Panish 1978) and bipolar transistors. Their
efficiency depends primarily on the ability of minority carriers to diffuse
through neutral material to a p-n junction or Schottky barrier where they
recombine with majority carriers. For this reason diffusion lengths have been
measured in a variety of semiconductor materials. The GaAs material was grown
by liquid phase epitaxy (LPE) at the Australian Nuclear Science and Technology
Organisation. The diffusion lengths measured for high purity ptype and n-type
LPE-GaAs samples were observed to be longer than any previously reported.
Measurements of minority carrier diffusion lengths for p-type and n-type GaAs
were carried out using an electron beam induced current (EBIC) technique.
