POLARIZATION-FIELDS AND BAND OFFSETS IN GAINP GAAS AND ORDERED/DISORDERED GAINP SUPERLATTICES/

Using the first-principles pseudopotential method we have calculated b and offsets between ordered and disordered Ga0.5In0.5P and between ord ered GaInP2 and GaAs. We find valence band offsets of 0.10 and 0.27 eV for the two interfaces with the valence band maximum on ordered GaInP 2 and GaAs, respectively. Using experimental band gaps these offsets i ndicate that the ordered/disordered Ga0.5In0.5P interface has type I b and alignment and that the ordered GaInP2/GaAs interface has type II a lignment. Assuming transitivity of the band offsets, these results sug gest a type I alignment between disordered Ga0.5In0.5P and GaAs and a transition from type I to type Il as the GaInP side becomes more order ed. Our calculations also show that ordered GaInP2 has a strong macros copic electric polarization. This polarization will generate electric fields in inhomogeneous samples, strongly affecting the electronic pro perties of the material. (C) 1996 American Institute of Physics.