LIQUID-PHASE EPITAXIAL P-TYPE ZNSE GROWTH FROM A SE SOLUTION AND FABRICATION OF PN JUNCTIONS WITH DIFFUSED N-TYPE LAYERS

High concentration p-type epitaxial ZnSe layers are grown by the tempe rature difference method under controlled Zn vapor pressure (TDM-CVP) liquid phase epitaxy (LPE) from a Se solution. The hole concentration of the epitaxial layers grown at 950 degrees C under a Zn vapor pressu re of 3.0 atm increases with increasing the amount of Na(2)e until 0.5 x10(-2) mol% in Se solution but decreases with an amount of Na2Se abov e 0.5x10(-2) mol%. The decrease of the hole concentration is related t o the appearance of a luminescence band with a peak at 2.696 eV in the CL spectra. These trends are in accordance with Na2S- or LiN3-doped e pitaxial layers. Na2Se-doped ZnSe layers show a high carrier concentra tion(p(max)approximate to 1x10(18) cm(-3)) and an almost undetectable deep level luminescence but an inhomogeneous surface morphology with m any interrupted growth areas. On the other hand, Na2S- or LiN3-doped Z nSe layers show a relatively low carrier concentration (<10(17) cm(-3) ) but an almost undetectable deep lever luminescence and a homogeneous surface morphology with macrosteps. Photocapacitance measurements are applied to LiN3-doped p-type epitaxial layers and revealed dominant d eep levels at E(v)+2.55 eV, which are suggested to compensate shallow accepters. pn junction diodes are fabricated by Ga diffusion for n-typ e layers from a Zn solution into the Na2S-doped p-type epitaxial ZnSe layer and they emit pure blue light with a wavelength of 471 nm at roo m temperature.