Low-threshold-current-density AlGaN-cladding-free m-plane InGaN/GaN laser diodes

Abstract

We demonstrate AlGaN-cladding-free m-plane InGaN/GaN laser diodes with threshold current densities that are comparable to state-of-the-art c-plane InGaN/GaN laser diodes. Thick InGaN waveguiding layers and a relatively wide active region with three 8 nm quantum wells were used to provide adequate refractive index contrast with the GaN cladding layers, thus eliminating the need for AlGaN cladding layers. Despite the large active region volume, lasing was achieved at a threshold current density of 1.54 kA/cm2, suggesting that the realization of even lower threshold current densities should be possible by reducing the number of quantum wells in the active region.

On the Effect of Step-Doped Quantum Barriers in InGaN/GaN Light Emitting Diodes

“…Recently, c-plane III-Nitride quantum wells with embedded "delta" novel materials have proved to be effective in enhancing the electron-hole wave function overlap, therefore increasing the radiative recombination rates [23]- [26]. The strain induced spatial separation of electron-hole wave functions can further be completely eliminated in the non-polar quantum wells and increased radiative recombination rates can thus be obtained [27], [28]. It has also been shown that the material quality and the device performance can be substantially improved by introducing Si doping in quantum barriers [29]- [31].…”

Semipolar GaN-based laser diodes for Gbit/s white lighting communication: devices to systems

“…[25][26][27] Recent studies have shown significant improvements in high-power performance and lower threshold current densities of semipolar/nonpolar LDs. [28][29][30][31][32] It is also expected to have high modulation bandwidth and high-speed performance for semipolar/nonpolar LDs due to higher differential gain and lower threshold current density as shown in Eq. After the MOCVD growth and p-GaN activation, the sample was first cleaned by aqua regia (1:3 HNO 3 :HCl).…”

Interface phonon modes in the [AlN/GaN]20 and [Al0.35Ga0.65N/Al0.55Ga0.45N]20 2D multi-quantum well structures

“…[4][5][6][7][8][9] The SLs and MQWs of AlGaN/GaN with different Al percentages are used as active region, as well as buffer, carrier confining and electron blocking layers (EBL) to improve the internal and external quantum efficiency of blue, UV and deep-UV LEDs and LDs. [4][5][6][7][8][9] The Raman spectroscopy demands the wave vector q  0 selection rule for the observation of phonon modes in the infinite crystals as a consequence of the infinite periodicity of the crystal lattice. Whereas, in the case of optical phonons in polar semiconductor SLs and MQWs; the approximation of negligible crystal-momentum transfer for the backscattered waves as in the case of bulk crystal may not be true for certain phonon modes of SLs or MQWs with a larger periodicity.…”

“…[1][2][3][4][5] Because of the capability to create two dimensional (2D) electron gas at the heterojunctions, the III-nitrides especially AlGaN/GaN MQWs and SLs are used for developing high electron mobility transistors (HEMT) along with the heterojunction field effect transistors (HJFET) and bipolar transistors. [4][5][6][7][8][9] The SLs and MQWs of AlGaN/GaN with different Al percentages are used as active region, as well as buffer, carrier confining and electron blocking layers (EBL) to improve the internal and external quantum efficiency of blue, UV and deep-UV LEDs and LDs. [4][5][6][7][8][9] The Raman spectroscopy demands the wave vector q  0 selection rule for the observation of phonon modes in the infinite crystals as a consequence of the infinite periodicity of the crystal lattice.…”