Photocurrent and photoluminescence of a single self-assembled quantum dot in electric fields

We have fabricated single-quantum-dot photodiodes by embedding InGaAs quant um dots in the intrinsic region of an n-i-Schottky diode combined with near -field shadow masks. As a function of the bias voltage, we study one and th e same quantum dot in the two complementary regimes of photocurrent and pho toluminescence. The Stark shift of the exciton ground state continues monot onically in both regimes, confirming nicely the observation of the same qua ntum dot in photoluminescence and photocurrent. In the limit of high electr ic fields, we observe a broadening of the photocurrent linewidth from which we determine a strongly reduced exciton lifetime of below 1 ps. (C) 2001 A merican Institute of Physics.