Bandgap-adjustment and enhanced surface photovoltage in Y-substituted LaTa IV O 2 N

Microstructure controlled ammonolysis allowed the synthesis of oxynitrides La 1−x Y x Ta IV O 2 N ( x ≤ 0.3) and YTa(O,N) 3 of which the first ones showed a remarkable up-built of photovoltage even in the presence of reduced tantalum ( e.g. Ta 4+ ).