科研之友
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摘要
We have observed anti-Stokes photoluminescence from n-type free-standing GaN at room temperature. Such a process is caused by phonon-assisted absorption. When the excitation photon energy is sufficiently below the donor-acceptor transition energy, however, two-photon absorption becomes the dominant mechanism for anti-Stokes photoluminescence. By measuring the dependences of the photoluminescence spectra on temperature, excitation power and excitation photon energy, we have demonstrated that the donor-acceptor pair transition plays an important role in anti-Stokes photoluminescence. Our study could result in efficient laser cooling of semiconductors.
- 出版日期2009-5
