Influence of base-region thickness on the performance of Pnp transistor-VCSEL
2014 (English)In: Optics Express, ISSN 1094-4087, Vol. 22, no 22, 27398-27414 p.Article in journal (Refereed) Published
We have recently reported a 980nm GaAs-based three terminal Pnp transistor-vertical-cavity surface-emitting laser (TVCSEL) operating at room temperature with optical power up to 1.8mW. However, the current gain beta = Delta I-c/Delta I-b was near zero just before lasing and became negative after the lasing threshold. The main cause of the negative current gain was found to be a gradual and position-dependent forward-biasing (saturation) of the base-collector junction with increasing bias even before lasing threshold. In this article, detailed multi-physics device simulations are performed to better understand the device physics, and find ways to avoid the premature saturation of the base-collector junction. We have optimized the thickness of the base region as well as its doping concentration and the location of the quantum wells to ensure that the T-VCSEL is in the active mode throughout its range of operation. That is, the emitter-base junction is forward biased and base-collector junction is reversed biased for sweeping the excess charges out of the base region.
Place, publisher, year, edition, pages
2014. Vol. 22, no 22, 27398-27414 p.
Surface-Emitting Laser, Bipolar-Transistor, Operation
Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-156833DOI: 10.1364/OE.22.027398ISI: 000344004900093ScopusID: 2-s2.0-84919969277OAI: oai:DiVA.org:kth-156833DiVA: diva2:768020
FunderSwedish Research Council, 2010-4386
QC 201412032014-12-022014-12-022014-12-05Bibliographically approved