The electroabsorptive behavior of asymmetric triangular quantum wells (ATQW) in the active region of a p-i-n self-electro-optic effect device (SEED) structure is experimentally investigated. Excition transition energies are measured by photoluminescence and photocurrent spectroscopy at room temperature and at low temperatures. Room-temperature excitonic linewidths of 9.2 meV for a 265-Å ATQW have been obtained. The electric field modulation of excitonic absorption in ATQWs with compositional grading, both increasing and decreasing in the growth direction is presented. When compared with a similar rectangular quantum-well device, it is observed that ATQWs have intrinsically higher responsivity, comparable room temperature linewidths, and higher device on/off ratios.
Carrier-density dependence of the photoluminescence lifetimes in ZnCdSe/ZnSSe quantum wells at room temperature