The lateral ambipolar diffusion length in quantum dot lasers

A. Sobiesierski; D. Naidu; P. M. Smowton

doi:10.1117/12.874474

16 February 2011 The lateral ambipolar diffusion length in quantum dot lasers

A. Sobiesierski, D. Naidu, P. M. Smowton

Proceedings Volume 7953, Novel In-Plane Semiconductor Lasers X; 795306 (2011) https://doi.org/10.1117/12.874474
Event: SPIE OPTO, 2011, San Francisco, California, United States

Abstract

Using the segmented contact technique we determine the lateral out-diffusion current in shallow etched quantum dot ridges of different width and by fitting this out-diffusion data we obtain the ambipolar diffusion length as a function of the intrinsic carrier injection level. The measured data reveals two regimes of reduced diffusion that can be explained by a mechanism involving the thermal redistribution of carriers via the wetting layer. In a high performance 5 layer quantum dot structure operated at 350K the diffusion length varies between 0.75 and 1.5 μm as the peak modal gain increases from 5 to 11cm-1. In dot-in-well quantum dot samples fabricated into deep etched ridge lasers we demonstrate the improved performance and reduced ridge-width dependence of threshold current density as compared to quantum well material, which is identical except for the presence of the dots and wetting layer. For example in 6μm wide, 1500 μm long quantum dot ridges at 300K the threshold current density is 41% of that of the corresponding quantum well ridge. Furthermore, at 230K the threshold current density of the 6 μm ridge increases by a factor of 1.1 as compared to similar 20μm wide ridges whereas in quantum well ridge lasers the threshold current density increases by a factor of 3.2 for the same pair of ridge widths. This corresponds to a threefold decrease in the ridge width dependence of QD ridge lasers compared to QW based lasers. This different dependence on ridge width corresponds to the different lateral diffusion characteristics of the quantum well and self assembled quantum dot material.

Citation Download Citation

A. Sobiesierski, D. Naidu, and P. M. Smowton "The lateral ambipolar diffusion length in quantum dot lasers", Proc. SPIE 7953, Novel In-Plane Semiconductor Lasers X, 795306 (16 February 2011); https://doi.org/10.1117/12.874474

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available