CHARACTERISTICS OF INP EPITAXIAL LAYERS GROWN FROM SOLID PHOSPHORUS USING A VALVE PHOSPHORUS CRACKER CELL

We report the molecular beam epitaxial (MBE) growth of epitaxial InP u sing a valve phosphorus cracker cell in a range of cracking zone tempe rature (T-cr = 875 to 950 degrees C), V/III flux ratio (V/III = 1.2 to 9.3) and substrate temperature (T-s = 360 to 500 degrees C). The as-g rown epitaxial InP on InP (100) substrate was found to be n-type from Hall measurements. The background electron concentration and mobility exhibited a pronounced dependence on the cracking zone temperature, V/ III flux ratio and substrate temperature. Using a cracking zone temper ature of 850 degrees C, the highest 77 K electron mobility of 40 900 c m(2)/V s was achieved at a V/III ratio of 2.3 at substrate temperature (T-s) of 440 degrees C. The corresponding background electron concent ration was 1.74 X 10(15) cm(-3). The photoluminescence (PL) spectra sh owed two prominent peaks at 1.384 eV and 1.415 eV, with the intensity of the low energy peak becoming stronger at higher cracking zone tempe ratures. The PL full-width at half maximum (FWHM) was significantly re duced as the V/III ratio was lowered, indicating an improvement in the optical quality of the samples. The lowest PL FWHM achieved at 5 K wa s 6.3 meV. (C) 1998 Elsevier Science B.V. All rights reserved.