Effect of n(-)-layer thickness on green-light-emitting efficiency in nitrogen-doped GaP grown by liquid phase epitaxy

By comparing the photoluminescence intensity of a p-type crystal with that of a n-type crystal, we find that the p-side is the main light-emitting reg ion in the double-n structure nitrogen-doped GaP (GaP:N) material grown by liquid phase epitaxy (LPE). From this experimental result, we have created a simple theory regarding the minority-carrier-current distribution in the lower donor concentration layer in the double n-structure GaP:N material. T he theory describes that the interface of the lower, n(-), and the higher, n(+), donor concentration LPE n-layers has a reflection effect on the holes diffusing from p- to n-type crystal. When we decrease the thickness of the n(-)-layer and the majority-carrier concentration ratio of the n(-)- and n (+)-layers, the electron injection efficiency increases and the photolumine scence is correspondingly enhanced.