Optical gain in (Zn, Cd)Se–Zn(S, Se) quantum wells (original) (raw)
1998, Journal of the Optical Society of America B
We have investigated the mechanism of stimulated emission in ZnCdSe-ZnSSe quantum wells through optically pumped measurements of the gain spectrum in a variety of structures from 270 to 77 K. We also calculated the optical gain, using a model that includes many-body effects, and found excellent agreement between the calculated gain line shapes and our measurements. Under the conditions studied, which are close to those found in an operating laser diode, we conclude that the stimulated emission arises from an electronhole plasma in our samples, even down to 77 K. Although our measurements do not rule out exciton gain mechanisms at other temperatures or operating conditions, sensitive line-shape fitting does not require them in our case. However, our line-shape analysis does show that Coulomb enhancement is significant, even at room temperature.
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