The effects of substrate pre-annealing on deep level density in Mg-doped GaP liquid-phase epitaxy (LPE) layers were investigated by photocapacitance measurement. With annealing under optimum phosphorus-vapor pressure, concentration of deep donor at EC - 1.9-2.1 eV increased in undoped GaP substrate. Deep level densities in Mg-doped layers were also affected by pre-annealing of the substrates. Densities of dominant deep levels at EV + 0.85 eV and EV + 1.5 eV were an order of magnitude reduced and, in contrast, the level at EC - 2.1 eV in Mg-doped layer increased with long pre-annealing. This level at EC - 2.1 eV is supposed to be involved with P-rich-type nonstoichiometric defects, such as phosphorus interstitial atoms diffused from the surface of the substrate.
- Heat treatment
- Nonstoichiometric defect
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry