PHOTOLUMINESCENCE STUDIES ON INGAALP LAYERS GROWN BY LOW-PRESSURE METALORGANIC CHEMICAL VAPOR-DEPOSITION

The optical properties for In0.5(Ga1-xAl(x)0.5P (0 < x < 0.4) layers, grown by low-pressure Metalorganic Chemical Vapor Deposition, have been studied with photolominescence (PL) measurement. The PL intensity decreases with the increase of the Al composition (0 < x < 0.4). This dependence could not be accounted for only by the electron overflow from the GAMMA band to the X band. And the PL intensity is directly proportional to the excitation power at low temperature, below 50 K. On the other hand, the PL intensity is proportional to the second power of the excitation power at a high temperature range (> 200 K). These results indicate that non-radiative recombination centers bound to the GAMMA band in In0.5(Ga1-xAl(x)0.5P play a very important role in the radiation mechanism. PL dependence also shows these non-radiative recombination centers are thought to have strong relation to the aluminium substitution for In0.5(Ga1-xAl(x)0.5P.