INTERFACE-INDUCED CONVERSION OF INFRARED TO VISIBLE-LIGHT AT SEMICONDUCTOR INTERFACES

Efficient, low-temperature conversion of infrared light into visible l ight (red, orange, green) is reported at single heterojunctions and un doped quantum wells of GaAs and ordered AlxGa1-xInP2; an increase in p hoton energy of 700 meV is obtained. The signal originates from the hi gh-band-gap layers and disappears only if the excitation energy is tun ed below the GaAs band gap. The intensity of the up-converted photolum inescence (PL) is found to decrease significantly slower with increasi ng temperature than that of the regular PL and it remains observable u p to 200 K. Interface-induced cold Auger processes along with the pres ence of trapped states for both electrons and holes in these ordered a lloys account for this nonlinear mechanism. A colinear double-beam exp eriment confirms this.