Abstract:We report a systematic investigation of the transport properties of highly degenerate electrons in Ge-doped and Si-doped GaN epilayers prepared using the pulsed sputtering deposition (PSD) technique. Secondary-ion mass spectrometry and Hall-effect measurements revealed that the doping efficiency of PSD n-type GaN is close to unity at electron concentrations as high as 5.1 × 1020 cm−3. A record low resistivity for n-type GaN of 0.16 mΩ cm was achieved with an electron mobility of 100 cm2 V−1 s−1 at a carrier co… Show more
“…Figure 1 shows the RT electron mobility of highly Si-doped GaN grown on AlN/sapphire templates. In this figure, we also plotted the data for Si-doped GaN grown on GaN/sapphire templates and theoretically calculated mobility as a function of the compensation ratio θ , which were taken from our previous report 9 . The typical full width at half maximum (FWHM) values of the X-ray rocking curves of 0002 and 102 diffraction were 300 and 2000 arcsec for the samples on the AlN/sapphire templates, respectively.…”
Section: Resultsmentioning
confidence: 99%
“…This result also indicates that spontaneous polarization charges at the heterointerface between the GaN and AlN have little impact on the electron transport properties in highly n-type doped GaN grown on the AlN/sapphire templates.Figure 1Measured electron mobility of heavily Si-doped GaN on AlN/sapphire templates as a function of electron concentration. The experimental data for the samples grown on GaN/sapphire templates and the calculated electron mobility for a compensation ratio (0 < θ < 0.5) were taken from our previous report 9 .…”
Section: Resultsmentioning
confidence: 99%
“…Measured electron mobility of heavily Si-doped GaN on AlN/sapphire templates as a function of electron concentration. The experimental data for the samples grown on GaN/sapphire templates and the calculated electron mobility for a compensation ratio (0 < θ < 0.5) were taken from our previous report 9 .…”
Section: Resultsmentioning
confidence: 99%
“…Recently, we found that the use of a sputtering process, named pulsed sputtering deposition (PSD) 4 , is advantageous for donor or acceptor doping in nitride films such as GaN and AlN with high carrier mobilities 5–9 . For PSD-grown Si-doped GaN, the minimum resistivity was found to be as low as 1.6 × 10 −4 Ωcm with an electron concentration and mobility of 3.9 × 10 20 cm −3 and 100 cm 2 V −1 s −1 , respectively 9 . This is the lowest resistivity attained for n-type GaN to date.…”
We have characterized highly conductive Si-doped GaN films with a high electron mobility of 112 cm2V−1s−1 at an electron concentration of 2.9 × 1020 cm−3, prepared using pulsed sputtering deposition (PSD). With an increase in the doping concentration, the absorption edge was found to shift toward a higher energy level, owing to the Burstein-Moss effect, thus making this material suitable for the transparent conductive tunneling electrodes of visible and ultraviolet-A light-emitting diodes. The full width at half maximum value of the near-band-edge (NBE) emissions in a photoluminescence spectrum measured at 77 K was as small as 185 meV, even for the sample with the highest electron concentration of 2.9 × 1020 cm−3. Such sharp NBE emissions from PSD-grown heavily Si-doped GaN films can be explained by an analytical model with a low compensation ratio θ of around 0.1, which is consistent with the exceptionally high observed electron mobility. These results indicate the strong potential of the low-temperature PSD growth technique for the formation of high-quality, heavily Si-doped GaN.
“…Figure 1 shows the RT electron mobility of highly Si-doped GaN grown on AlN/sapphire templates. In this figure, we also plotted the data for Si-doped GaN grown on GaN/sapphire templates and theoretically calculated mobility as a function of the compensation ratio θ , which were taken from our previous report 9 . The typical full width at half maximum (FWHM) values of the X-ray rocking curves of 0002 and 102 diffraction were 300 and 2000 arcsec for the samples on the AlN/sapphire templates, respectively.…”
Section: Resultsmentioning
confidence: 99%
“…This result also indicates that spontaneous polarization charges at the heterointerface between the GaN and AlN have little impact on the electron transport properties in highly n-type doped GaN grown on the AlN/sapphire templates.Figure 1Measured electron mobility of heavily Si-doped GaN on AlN/sapphire templates as a function of electron concentration. The experimental data for the samples grown on GaN/sapphire templates and the calculated electron mobility for a compensation ratio (0 < θ < 0.5) were taken from our previous report 9 .…”
Section: Resultsmentioning
confidence: 99%
“…Measured electron mobility of heavily Si-doped GaN on AlN/sapphire templates as a function of electron concentration. The experimental data for the samples grown on GaN/sapphire templates and the calculated electron mobility for a compensation ratio (0 < θ < 0.5) were taken from our previous report 9 .…”
Section: Resultsmentioning
confidence: 99%
“…Recently, we found that the use of a sputtering process, named pulsed sputtering deposition (PSD) 4 , is advantageous for donor or acceptor doping in nitride films such as GaN and AlN with high carrier mobilities 5–9 . For PSD-grown Si-doped GaN, the minimum resistivity was found to be as low as 1.6 × 10 −4 Ωcm with an electron concentration and mobility of 3.9 × 10 20 cm −3 and 100 cm 2 V −1 s −1 , respectively 9 . This is the lowest resistivity attained for n-type GaN to date.…”
We have characterized highly conductive Si-doped GaN films with a high electron mobility of 112 cm2V−1s−1 at an electron concentration of 2.9 × 1020 cm−3, prepared using pulsed sputtering deposition (PSD). With an increase in the doping concentration, the absorption edge was found to shift toward a higher energy level, owing to the Burstein-Moss effect, thus making this material suitable for the transparent conductive tunneling electrodes of visible and ultraviolet-A light-emitting diodes. The full width at half maximum value of the near-band-edge (NBE) emissions in a photoluminescence spectrum measured at 77 K was as small as 185 meV, even for the sample with the highest electron concentration of 2.9 × 1020 cm−3. Such sharp NBE emissions from PSD-grown heavily Si-doped GaN films can be explained by an analytical model with a low compensation ratio θ of around 0.1, which is consistent with the exceptionally high observed electron mobility. These results indicate the strong potential of the low-temperature PSD growth technique for the formation of high-quality, heavily Si-doped GaN.
“…Such n-doped films exhibited improved properties with high electron concentrations of above 10 20 cm −3 and a mobility of above 100 cm 2 V −1 s −1 . 5,6 Furthermore, p-doping was achieved. 7 These results show the high potential of sputter deposition.…”
The formation of high‐quality n‐type AlN with a dislocation density of 2.8 × 108 cm−2 on sapphire (0001) using pulsed sputtering deposition (PSD) and high‐temperature (HT) annealing is demonstrated. The surface morphology of PSD‐grown AlN on AlN templates prepared by HT annealing consists of an ordered stepped‐and‐terraced structure with a step height of 1 ML. Si‐doped AlN on the HT‐annealed AlN template yields the high electron mobility of 141 cm2 V−1 s−1 at room temperature, which is attributed to the reduction in the dislocation density and compensating centers. These results indicate that the PSD is a promising epitaxial technique for the fabrication of ultraviolet (UV) light‐emitting diodes (LEDs) and future power devices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
