Study of Wide Bandwidth All Optical Wavelength Converter using Low Dimensional Quantum Well Structure

通过生长材料与衬底之间较大的晶格失配诱导的S-K生长模式自组装量子点的光学性质因其迷人的物理性质和在光电子器件中的巨大应用潜力而成为当前研究的热点。我们利用低压金属有机气相外延技术在(100InP)衬底上生长了InAs量子点。InAs量子点的生长过程如下。在InP衬底上生长3 nm GaInAs缓冲层后，提供TMI和TBA，并在生长中断过程中自形成InAs量子点。在实验中，我们得到了InAs点直径与生长温度、压力、供电时间和生长中断时间的关系。量子点密度与生长温度、压力、源供给时间和生长中断时间有很大关系。在生长温度为500℃、生长压力为15 Torr、光源供电时间为7秒、生长中断时间为60秒的条件下，得到了横向尺寸为16.7 nm的量子点。据我们所知，这种尺寸的量子点是InP衬底上最小的InAs点。我们已经生长了多层InAs/InP量子点。在低温(10K)下对单层InAs/InP量子点进行了光致发光测量，在1837 nm处有发射，半高宽为54.3 meV。该波长与计算结果吻合较好。

The optical properties of self-assembled quantum dots (QDs) via Stranski-Krastanov (S-K) growth mode, which is induced by relatively large lattice mismatch between growth material and substrate are currently a subject of intense investigation due to their fascinating physical properties and their strong potential for application in optoelectronics devices.We have shown the growth condition of InAs quantum dots (QDs) on (100)InP substrate under the S-K growth mode by using low pressure metalorganic vapor phase epitaxy (MOVPE). The growth procedure of InAs QDs was as follows. After the growth of 3nm GalnAs buffer layer on the InP substrate, TMI and tBA were supplied and InAs QDs were self-formed during the growth interruption. In the experiment, we obtained the relation between InAs dot diameter and the growth temperature, pressure, and source supplied time, and growth interruption time. The QD density had a greatly dependence on the growth temperature, pressure, and source supplied time and growth interruption. The lateral size of 16.7nm QDs was obtained under a 500 ℃ growth temperature and a 15Torr growth pressure and a 7sec source supplied time and a 60sec growth interruption time. As far as we know this QDs size is the smallest InAs dot on the InP substrate. And we have grown the multi-stacked InAs/InP QDs. The PL measurements of the single-layer InAs/InP QDs were performed at low temperature (10K), and exhibited an emission (FWHM of 54.3meV) around the wavelength of 1837nm. This wavelength was well agreed with the calculation result.