Ordering effects on the electrical characteristics of Ga _0.5In_0.5P grown by metalorganic chemical vapor deposition

The relationship between electrical characteristics and structural ordering in undoped and Zn-doped Ga_0.5In_0.5P films grown by metalorganic chemical vapor deposition is investigated. The Schottky diode was used to examine the electrical properties of the undoped samples with ordered and disordered structures. With the same carrier concentration (∼1.5×10¹⁶ cm^-3), the diode fabricated on the ordered film shows a degraded current-voltage characteristic. As the carrier concentration of Zn-doped Ga_0.5In_0.5P increases above 1.5×10¹⁸ cm^-3, the energy gap of the ordered structure is larger than that of the disordered structure. It was found that the hole mobility of the ordered film is lower than that of the disordered film with the similar doping level. The behavior could be attributed to the existence of antiphase boundaries within the ordered structure. The antiphase boundaries can act as recombination centers and/or scattering centers and result in the extraordinary electrical properties of the ordered samples.