Electrical and deep-level characterization of GaP1−xNx grown by gas-source molecular beam epitaxy

Abstract

We have investigated electrical properties and deep levels of n-GaP1−xNx (x=0%−0.62%) grown on (100) n-GaP substrates by gas source molecular beam epitaxy. The x-ray photoelectron spectroscopy results showed no significant effects on the chemical bonding status of the host Ga-P matrix by the incorporation of small amounts of N atoms. In the Raman spectra, the zone-edge GaP-like vibration was observed at 387 cm−1, originating from alloy disorder or local distortion of the GaP1−xNx lattice. The electrical properties of the GaP1−xNx surfaces were characterized using a Schottky contact structure. An ideality factor of 1.10–1.15 and a Schottky barrier height of 1.1 eV were obtained from the current-voltage characteristics of Ni∕GaP1−xNx diodes, indicating good interface quality. The thermal admittance spectroscopy clearly detected the Si donor level with an activation energy of 84±4 meV in GaP and GaP1−xNx. For the GaP1−xNx samples, we observed deep levels probably associated with N-induced defects such as N-N pairs, N clusters, and an N-containing complexes.