Properties of high-resistivity Li-diffused GaAs

The compensation of electrical conductivity of a wide range of n-type and p-type GaAs diffused with the group-I element Li has been investigated. For diffusion temperatures exceeding 700-800 /spl deg/C a full compensation of all conducting samples is obtained in undoped, n-type and p-type samples. The fully compensated samples show resistivity higher than 10/sup 7/ /spl omega/ cm. The photoluminescence of these samples is characterized by excitation dependent emissions which shift to lower energies with increasing degree of compensation. Electrical and optical properties of the Li-compensated samples are discussed in terms of buried Schottky barriers and fluctuations of the electrostatic potential in impure, compensated crystals.