@article{bagheri_quinones-garcia_khachariya_loveless_guan_rathkanthiwar_reddy_kirste_mita_tweedie_et al._2023, title={High conductivity in Ge-doped AlN achieved by a non-equilibrium process}, volume={122}, ISSN={["1077-3118"]}, url={https://doi.org/10.1063/5.0146439}, DOI={10.1063/5.0146439}, abstractNote={Highly conductive Ge-doped AlN with conductivity of 0.3 (Ω cm)−1 and electron concentration of 2 × 1018 cm−3 was realized via a non-equilibrium process comprising ion implantation and annealing at a moderate thermal budget. Similar to a previously demonstrated shallow donor state in Si-implanted AlN, Ge implantation also showed a shallow donor behavior in AlN with an ionization energy ∼80 meV. Ge showed a 3× higher conductivity than its Si counterpart for a similar doping level. Photoluminescence spectroscopy indicated that higher conductivity for Ge-doped AlN was achieved primarily due to lower compensation. This is the highest n-type conductivity reported for AlN doped with Ge to date and demonstration of technologically useful conductivity in Ge-doped AlN.}, number={14}, journal={APPLIED PHYSICS LETTERS}, author={Bagheri, Pegah and Quinones-Garcia, Cristyan and Khachariya, Dolar and Loveless, James and Guan, Yan and Rathkanthiwar, Shashwat and Reddy, Pramod and Kirste, Ronny and Mita, Seiji and Tweedie, James and et al.}, year={2023}, month={Apr} }
 @article{rathkanthiwar_reddy_moody_quinones-garcia_bagheri_khachariya_dalmau_mita_kirste_collazo_et al._2023, title={High p-conductivity in AlGaN enabled by polarization field engineering}, volume={122}, ISSN={["1077-3118"]}, url={https://doi.org/10.1063/5.0143427}, DOI={10.1063/5.0143427}, abstractNote={High p-conductivity (0.7 Ω−1 cm−1) was achieved in high-Al content AlGaN via Mg doping and compositional grading. A clear transition between the valence band and impurity band conduction mechanisms was observed. The transition temperature depended strongly on the compositional gradient and to some degree on the Mg doping level. A model is proposed to explain the role of the polarization field in enhancing the conductivity in Mg-doped graded AlGaN films and the transition between the two conduction types. This study offers a viable path to technologically useful p-conductivity in AlGaN.}, number={15}, journal={APPLIED PHYSICS LETTERS}, author={Rathkanthiwar, Shashwat and Reddy, Pramod and Moody, Baxter and Quinones-Garcia, Cristyan and Bagheri, Pegah and Khachariya, Dolar and Dalmau, Rafael and Mita, Seiji and Kirste, Ronny and Collazo, Ramon and et al.}, year={2023}, month={Apr} }
 @article{bagheri_klump_washiyama_breckenridge_kim_guan_khachariya_quinones-garcia_sarkar_rathkanthiwar_et al._2022, title={Doping and compensation in heavily Mg doped Al-rich AlGaN films}, volume={120}, ISSN={["1077-3118"]}, DOI={10.1063/5.0082992}, abstractNote={Record low resistivities of 10 and 30 Ω cm and room-temperature free hole concentrations as high as 3 × 1018 cm−3 were achieved in bulk doping of Mg in Al0.6Ga0.4N films grown on AlN single crystalline wafer and sapphire. The highly conductive films exhibited a low ionization energy of 50 meV and impurity band conduction. Both high Mg concentration (>2 × 1019 cm−3) and low compensation were required to achieve impurity band conduction and high p-type conductivity. The formation of VN-related compensators was actively suppressed by chemical potential control during the deposition process. This work overcomes previous limitations in p-type aluminum gallium nitride (p-AlGaN) and offers a technologically viable solution to high p-conductivity in AlGaN and AlN.}, number={8}, journal={APPLIED PHYSICS LETTERS}, author={Bagheri, Pegah and Klump, Andrew and Washiyama, Shun and Breckenridge, M. Hayden and Kim, Ji Hyun and Guan, Yan and Khachariya, Dolar and Quinones-Garcia, Cristyan and Sarkar, Biplab and Rathkanthiwar, Shashwat and et al.}, year={2022}, month={Feb} }
 @article{bagheri_quinones-garcia_khachariya_rathkanthiwar_reddy_kirste_mita_tweedie_collazo_sitar_2022, title={High electron mobility in AlN:Si by point and extended defect management}, volume={132}, ISSN={["1089-7550"]}, url={https://doi.org/10.1063/5.0124589}, DOI={10.1063/5.0124589}, abstractNote={High room temperature n-type mobility, exceeding 300 cm 2 /Vs, was demonstrated in Si-doped AlN. Dislocations and C N −1 were identified as the main compensators for AlN grown on sapphire and AlN single crystalline substrates, respectively, limiting the lower doping limit and mobility. Once the dislocation density was reduced by the growth on AlN wafers, C-related compensation could be reduced by controlling the process supersaturation and Fermi level during growth. While the growth on sapphire substrates supported only high doping ([Si] > 5 × 10 18 cm −3 ) and low mobility (∼20 cm 2 /Vs), growth on AlN with proper compensation management enabled controlled doping at two orders of magnitude lower dopant concentrations. This work is of crucial technological importance because it enables the growth of drift layers for AlN-based power devices.}, number={18}, journal={JOURNAL OF APPLIED PHYSICS}, author={Bagheri, Pegah and Quinones-Garcia, Cristyan and Khachariya, Dolar and Rathkanthiwar, Shashwat and Reddy, Pramod and Kirste, Ronny and Mita, Seiji and Tweedie, James and Collazo, Ramon and Sitar, Zlatko}, year={2022}, month={Nov} }