Optically pumped deep-UV multimode lasing in AlGaN double heterostructure grown by molecular beam homoepitaxy

Deurzen, Len van; Page, Ryan; Protasenko, Vladimir; Nomoto, Kazuki; Xing, Huili Grace; Jena, Debdeep

doi:10.1063/5.0085365

Cited by 9 publications

(1 citation statement)

References 41 publications

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“…There is a strong desire to study the growth of N-polar AlN on bulk AlN substrates to eliminate the above problems. Moreover, a homoepitaxial platform for N-polar AlN could offer new possibilities in deep-ultraviolet (UV) laser diodes and light-emitting diodes 26,27 . Besides suppressing optical losses due to the reduction in dislocation and point defect densities by growth on single-crystal AlN 28 , the N-polarity can improve the light output in deep-UV emitters by enhancing the injection efficiency 29 .…”

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confidence: 99%

Molecular Beam Homoepitaxy of N-polar AlN on bulk AlN substrates

Singhal¹,

Encomendero²,

Cho³

et al. 2022

Preprint

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N-polar AlN epilayers were grown on the N-face of single crystal bulk AlN substrates by plasma assisted molecular beam epitaxy (PA-MBE). A combination of in situ thermal deoxidation and Al-assisted thermal desorption at high temperature helped in removing native surface oxides and impurities from the N-polar surface of the substrate enabling successful homoepitaxy. Subsequent epitaxial growth of AlN layer on the in situ cleaned substrates, grown in sufficiently high Al droplet regime, exhibited smooth surface morphologies with clean and wide atomic steps. KOH etch studies confirmed the N-polarity of the homoepitaxial films. Secondary ion mass spectrometry profiles show Si and H impurity concentrations below the noise levels, whereas O and C impurities concentrations of ∼ 8 × 10 17 atoms/cm 3 and ∼ 2 × 10 17 atoms/cm 3 are observed respectively. Though the structural defect densities are low, they interestingly appear as inversion domains of different dimensionalities.

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mentioning

confidence: 99%

Molecular Beam Homoepitaxy of N-polar AlN on bulk AlN substrates

Singhal¹,

Encomendero²,

Cho³

et al. 2022

Preprint

Self Cite

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Gain Characteristics of Optically Pumped UVC Lasers with Wide AlGaN Single‐Quantum‐Well Active Regions

Cardinali,

Kölle,

Schulz

et al. 2024

Physica Status Solidi (a)

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Herein, the lasing threshold and gain characteristics of ultraviolet‐C optically pumped edge‐emitting lasers with thick single‐quantum‐well (SQW) active regions are investigated by the variable‐stripe length method. Positive net modal gain is observed in lasers with AlGaN‐based SQWs with thicknesses up to 12 nm. The lasers show a reduction of the threshold power density with increasing SQW thickness, with the lowest threshold of 1.3 MW cm−2 achieved for a 9 nm SQW laser. The high gain and low threshold in lasers with thick quantum wells are attributed to lasing from excited states, where the polarization fields are screened by the carriers in the fundamental state and the barriers, thus recovering larger electron and hole wavefunctions overlap. These findings are supported by k · p simulations, and for a 9 nm SQW, the calculation predicts a contribution of the fundamental transition to the gain of 75% for non‐resonant optical excitation and below 1% for resonant optical or electrical excitation.

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