LIGHT-EMITTING-DIODES FROM MOVPE-GROWN P-DOPED AND N-DOPED II-VI COMPOUNDS

A critical review is given of the present state, the problems and the prospects of MOVPE-growth of II-VI LEDs. It is shown that MOVPE-growth on (001)GaAs substrates occurs preferentially in a three-dimensional growth mode independent of substrate preparation. ZnSxSe1-x grows in g ood quality over the whole range of composition x. Good quality of Znx Cd1-xSe was only obtained for low Cd-concentrations. Improvements can be expected from the use of new precursors. The n-doping of ZnSe and Z nSxSe1-x presents no problem when n-butylchloride is used. Carrier con centrations can be as high as n greater than or equal to 10(18). Vario us nitrogen compounds have been used to achieve p-doping of ZnSe by MO VPE. We show that quite large concentrations of nitrogen can be incorp orated by photoassisted MOVPE with phenylhydrazine as precursor. The n itrogen doped samples are usually highly compensated independent from the special doping procedure. Proper annealing can activate at least p art of the incorporated nitrogen. The preparation of appropriate diode structures presents no special problems, however their room temperatu re (RT) luminescence efficiency is still low but may be considerably i mproved with increasing purity of precursors.