P+/N GAAS-ALGAAS HETEROSTRUCTURES GROWN BY GAS SOURCE MBE USING GASEOUS P-TYPE AND N-TYPE DOPANT SOURCES

We report on the first growth of p+/N GaAs-Al(x)Ga1-xAs heterostructures using all gaseous sources by gas source MBE (GSMBE). GaAs was doped p-type (1.3 x 10(20) cm-3) using trimethylgallium as both a dopant and group III source and Al(x)Ga1-xAs (x = 0-0.28) was doped n-type (5 x 10(17) cm-3) using uncracked disilane as an n-type dopant and triethylgallium and triethylaluminium as group III sources. In both cases 100% arsine was used as the group V source. The current-voltage ideality factor of the heterojunctions was found to depend on the aluminium mole fraction of Al(x)Ga1-xAs (x = 0.12, 0.23, 0.28) and the width (DELTA-s = 5, 10, 20 nm) of an undoped GaAs spacer layer at the heterojunction. A value of 1.17 was obtained for a heterostructure with x = 0.23 and DELTA-s = 20 nm.