ELECTRICAL, OPTICAL-PROPERTIES, AND SURFACE-MORPHOLOGY OF HIGH-PURITY INP GROWN BY CHEMICAL BEAM EPITAXY

High purity InP layers have been grown by chemical beam epitaxy using H-2 as the carrier gas for transporting the metal alkyl trimethylindium into the growth chamber. InP layers exhibiting Hall mobility as high as 238 000 cm(2)/V s at 77 K and with a peak value of 311 000 cm(2)/V s at 50 K and residual Hall concentration of 6X10(13) cm(-3) at 77 K were grown at 500 degrees C using a low V/III ratio (2.2) and a phosphine (PH3) cracking cell temperature of 950 degrees C. The 4.2 K photoluminescence spectra were dominated by donor bound exciton (D-0,X)(n) up to n=6 and free exciton (X) transitions for InP layers grown above 500 degrees C. All the InP samples exhibited very weak acceptor related photoluminescence transitions indicating very low concentration of accepters. The energy of these transitions suggests that Mg is the major residual acceptor. Donor impurity identification by high resolution magnetophotoluminescence indicated that S and Si are the major impurities. PH3 has been found to be the major source of S impurities in the present study.