| About this Abstract |
| Meeting |
2011 Electronic Materials Conference
|
| Symposium
|
2011 Electronic Materials Conference
|
| Presentation Title |
R10, Growth of III-Sb VECSELs for High-Power Continuous Wave Operation |
| Author(s) |
P. Ahirwar, Thomas J Rotter, Alexander R Albrecht, Stephen P. R. Clark, Victor Patel, Simon Reissmann, Huiwen Xu, Christopher P Hains, Larry Ralph Dawson, Ganesh Balakrishnan, Jorg Hader, Jerome V Moloney |
| On-Site Speaker (Planned) |
P. Ahirwar |
| Abstract Scope |
We present growth and design of III-Sb vertical-external-cavity-surface-emitting-lasers (VECSELs) on GaAs substrates for continuous-wave (CW) operation. The lack of effective thermal management in a VECSEL active region is the most significant limitation for the CW operation. Transparent intracavity heat spreaders such as natural diamond can efficiently extract the generated heat but the high cost, stimulated photon absorption and unwanted etalon effects limit their usefulness. Another approach that has yielded excellent result is the removal of the substrate on which the VECSEL is grown and subsequently bonding the chip to a low-cost CVD diamond such that the diamond is outside the cavity. This configuration is however very difficult to achieve in antimonide semiconductors on account of poor etch stop layers in the 6.1 Å family. In this presentation, we demonstrate the bonding of III-Sb VECSELs to CVD diamond by first growing these lasers on GaAs substrates. The growth of such lasers on GaAs provides us with unique epitaxial designs that can take advantage of the superior AlAs based etch-stop layers and therefore vastly improved etch results. We shall investigate two kinds of VECSEL structures based on the growth of III-Sb epilayers on the GaAs lattice constant - (a) a Top-emitter design and (b) a Bottom-emitter design. The structures are designated as top or bottom emitters based on the sequence in which the DBR and active regions are grown. In a Top-emitter VECSEL structure the antimonide quantum wells and barriers are typically grown on top of a MOCVD grown GaAs/AlGaAs DBR. The antimonide growth is done in a molecular beam epitaxy (MBE) reactor while the GaAs/AlGaAs DBRs are grown using metal-organic chemical vapor deposition (MOCVD). In case of a bottom-emitter VECSEL structure, the antimonide active regions are grown on a GaAs substrate followed by an AlSb/GaSb DBR. The top-emitter while grown on GaAs/AlGaAs DBRs is extremely difficult to process due to the fact that the bonding of the laser is done after the removal of the substrate, making it very difficult to handle the 7 µm thick VECSEL structure. The bottom emitter design is more suitable for processing since the laser is first bonded to the diamond followed by substrate removal. The CVD diamond therefore acts as wafer handle for the VECSEL epi-layers that have been released from the substrate. We shall in the presentation describe in greater detail the growth of the above structures. We shall also present characterization results of the semiconductors through techniques such as X-ray diffraction (XRD), photoluminescence (PL), surface Nomarski microscopy and atomic force microscopy (AFM). |
| Proceedings Inclusion? |
Undecided |