AlAsSb/GaSb doped distributed Bragg reflectors for electrically pumped VCSELs emitting around 2.3 µm

Abstract

This paper is dedicated to the study of electrical and optical properties of four different doped 21.5 pairs AlAsSb/GaSb distributed Bragg reflectors lattice-matched to GaSb and designed for the fabrication of electrically pumped VCSELs emitting around 2.3 µm. Three different doping profiles have been carried out: n-bulk doping, n-delta doping and p-bulk doping. An n-type bulk doped Bragg mirror with step composition at GaSb/AlAsSb interfaces was also tested. The n-type bulk doped sample with sharp interfaces exhibited the best electrical properties, a voltage drop per pair of 25 mV and a specific resistance of 1 × 10 −4 cm 2 at 1 kA cm −2 . Moreover, optical losses as low as 5-10 cm −1 have been measured for n-type doped mirrors.

Room temperature continuous wave operation of electrically-injected Sb-based RC-LED emitting near

“…This high value is mainly due to the p-doped top AlAsSb/GaSb Bragg mirror. Moreover, the diode threshold voltage is of about 3.5 V, another relatively high value in agreement with the voltage drop per pair in the AlAsSb/GaSb doped Bragg mirrors [12]. In Fig.…”

“…In the cavity, each series is positioned with a multiple optical thickness of λ/2 in order to maximize the gain in the structure. According to a previous published work [12], the n-doping profile of the bottom Bragg mirror was a bulk-like one with sharp interfaces and a carrier concentration of 1.2 × 10 18 at. cm −3 in both AlAs 0.07 Sb 0.93 and GaSb layers to optimize its electrical conduction properties.…”

GaSb-based VCSELs emitting in the mid-infrared wavelength range (2–3μm) grown by MBE

“…Moreover both top and bottom Bragg mirrors are N-type doped to avoid the use of a P-type Bragg mirror that presents poor electrical and optical properties [12]. In the monolithic structures presented here, the electron/hole conversion occurs in an InAsSb (n ++ )/GaSb (p ++ ) tunnel junction (TJ) located at a node of the field intensity to reduce absorption.…”

“…Both mirrors are Te-doped with a concentration of 1.2 Â 10 18 cm À3 in order to optimize their electrical conduction properties [12]. The GaSb-AlAsSb system exhibits a high refractive index and a constant contrast between 2 and 3 mm (Dn$0.6).…”

Parametrization of the Optical Constants of AlAsxSb1-x Alloys in the Range 0.74-6.0 eV

“…AlAsSb-based systems have been widely investigated for high-speed optoelectronic device applications such as ultrafast cross-phase modulators [1], quantum-cascade lasers [2], distributed Bragg reflectors [3], ultrafast all-optical switches using intersubband transitions [4], and photodetectors [5,6]. The optical properties such as complex refractive index ñ = n + ik, dielectric function ε = ñ 2 = ε 1 + iε 2 , and interband transitions including the band gap of AlAsSb are needed for further device optimization [7], such as designs for distributed feedback grating waveguides [4] and simulations to predict the performance of solar cells [8,9].…”