P‐Type Dopants for GaP Green Light Emitting Diodes

Abstract

In an effort to reduce the red Zn‐O emission in green LED's, acceptors other than Zn were considered. Crystals were grown and green LED's fabricated from C‐ and Mg‐doped material. In the C‐doped crystals a half‐power dependence of as a function of partial pressure up to a maximum attainable of at 900°C was found. Mg‐doped crystals were grown with up to 1019 cm−3. In double LPE green LED's fabricated from a C,N‐doped layer grown on a Te,N‐doped layer, the external electroluminescent quantum efficiency, η, was as high as 0.1% at 200 A/cm2. For single liquid phase epitaxy (LPE) diodes with a Mg,N‐doped p‐layer, . For the acceptors Be and Mg (and also for Si and Al) thermodynamic calculations are presented which consider the formation of the nitride of the dopant through the interaction with the used to simultaneously dope the crystals with N. These calculations show that at typical LPE growth temperatures and under conditions where the Ga is saturated with N, the order of increasing solubility is . The low solubility of Al precludes the growth of heavily N‐doped from Ga‐rich melts. These calculations also predict the low which results with simultaneous Si and N doping. No such reaction involving the formation of a nitride limits the solubility of C during the LPE growth process.