2-DIMENSIONAL ELECTRON GASES IN LOW-PRESSURE METALORGANIC VAPOR-PHASE EPITAXIALLY GROWN INGAP HOMOJUNCTIONS

We present modulation-doped ordered-InGaP/disordered-InGaP homojunctions grown, lattice matched to GaAs, by metalorganic vapour phase epitaxy. Capacitance-voltage (C-V) profiling techniques, temperature-dependent Hall, Shubnikov-De Haas and photoluminescence measurements have been used for characterization. The C-V measurements show a narrow profile at the homointerface with an order of magnitude reduction in carrier density within 3 nm. From temperature dependent Hall measurements, typical two-dimensional behaviour is observed with sheet carrier densities as high as 3.6 x 10(13) cm(-2) (T < 100 K). No carrier freeze-out and constant mobilities around 850 cm(2) V-1 s(-1) below T = 100 K are observed. The 300 K channel conductivity of this new type of junction is 3.2 x 10(-3) Omega(-1), which is higher than reported in other two-dimensional electron gases. Shubnikov-De Haas measurements indicate the presence of two occupied excited subbands. The photoluminescence measurements clearly show a moving emission which involves the 2DEG.