The BEEM technique has also been used to measure conduction band offsets, which are critical for the design of new heterostructure devices such as transistors, lasers, etc., in the ordered GaInP/GaAs semiconductor system. Traditional methods based on current-voltage (I-V) and capacitance-voltage (C-V) measurements have long yielded highly varying results for the GaInP/GaAs system. Recent theoretical calculations have shown that the electronic band structure depends markedly on the degree of ordering, i.e., the possible alternate stacking of Ga atoms and In atoms in an ordered- instead of a random- array. By careful control of the conditions of crystal growth, it is believed that the order parameter can be changed although the degree of order still varies spatially. Concurrent STM and BEEM measurements have been used to spatially map out simultaneously the ordered domains and the conduction band offsets as a function of ordering (see paper). These measurements once again show the power of BEEM to provide new information on electronic transport in semiconductors on a local scale, not possible by any other technique.