ELECTRICAL AND OPTICAL-PROPERTIES OF INP GROWN AT DIFFERENT CRACKING TEMPERATURE AND V III RATIO USING A VALVE PHOSPHORUS CRACKER CELL/

We report the molecular beam epitaxial (MBE) growth of epitaxial InP u sing a valve phosphorous cracker cell at a range of cracking zone temp erature (T-cr = 875-950 degrees C) and V/III flux ratio (V/III = 1.2-9 .3). The as-grown epitaxial InP on InP(100) substrate was found to be n-type from Hall measurements. The background electron concentration a nd mobility exhibited a pronounced dependence on the cracking zone tem perature and V/III flux ratio. Using a cracking zone temperature of 85 0 degrees C, the highest 77 K electron mobility of 25500 cm(2)/V s was achieved at a V/III ratio of 2.3 at a substrate temperature (T-s) of 480 degrees C. The corresponding background electron concentration was 5.65 x 10(15) cm(-3). The photoluminescence (PL) spectra showed two p rominent peaks at 1.384 and 1.415 eV, with the intensity of the low-en ergy peak becoming stronger at higher cracking zone temperatures. The PL full-width at half-maximum (FWHM) showed a significant reduction as the V/III ratio was lowered, indicating an improvement in the optical quality of the samples. The lowest PL FWHM achieved was 6.3 meV. (C) 1998 Elsevier Science B.V. All rights reserved.