《華年日拾:梁駿吾院士80華誕記懷》為中國(guó)科學(xué)院半導(dǎo)體研究所提供了寶貴的圖文資料,可供從事半導(dǎo)體材料和材料物理學(xué)等相關(guān)專(zhuān)業(yè)的科研人員和管理工作者參考。
5 Conclusion
Time-dependent thermal simulation for ridge geometry InGaN MQW LDs was carried out with a two-dimensional model.A high temperature in the waveguide layer and large temperature step between regions under and outside ridge are generated due to the poor thermal conductivity of the sapphire substrate and the large threshold current and voltage.The temperature step in-creases rapidly with time during the initial several hundred nanoseconds and then remains con-stant.The temperature step is thought to have a strong influence on the dynamic characteristics of the LDs. Time-resolved measurements of L-I curves, far-field pattern, and spectra of the InGaN LDs under pulsed operation were performed.Results show that the temperature step leads to better confinement of high order modes and a lower threshold current and a higher slope effi-ciency of the device while a high temperature in the active layer results in a drastic decrease in slope efficiency.
References
[1]Nakamura s, Senoh M, Nagahama S, et al.InGaN/GaN/A1GaN-based laser diodes with modulation-doped strained-layer superlattiees grown on an epitaxially laterally overgrown GaN substrate.Appl Phys Lett, 1998,72 (2) :211.
[2]Kneissl M,Bour D P,Van de Walle C G,et al.Room-temperature continuous-wave operation of InGaN muhiple-quantunr well laser diodes with an asymmetric waveguide structure.Appl Phys Lett, 1999,75 (4) :581.
[3]Goto S, Ohta M, Yabuki Y, et al.Super high-power A1GalnN-based laser diodes with a single broad-area stripe emitter fab-ricated on a GaN substrate.Phys Status Solidi A,2003,200( 1 ) :122.
[4]Kahen K B, Shantharama L G, Shepherd J P, et al.Single depressed-index cladding ridge waveguide laser with a low aspect ratio.Appl Phys Lett, 1993,62(12) : 1317.