Time-resolved spectroscopy of Zn- and Cd-doped GaN

Bergman, Peder; Gao, Ying; Ḿonemar, B.; Holtz, P. O.

doi:10.1063/1.338366

Cited by 58 publications

(30 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Bergman et al used photoluminescence (PL) to derive an ionization energy of 0.34 eV for Zn. 51 Doping with Zn has not resulted in p-type conductivity, presumably due to the large ionization energy of the Zn acceptor. Experimental results about Be are inconclusive: Brandt et al have reported high levels of p-type doping using Be in MBE, provided oxygen is present as a co-dopant.…”

Section: Alternative Acceptorsmentioning

confidence: 99%

Doping of AlGaN Alloys

Walle

Stampfl

Neugebauer

et al. 1999

MRS Internet j. nitride semicond. res.

View full text Add to dashboard Cite

Nitride-based device structures for electronic and optoelectronic applications usually incorporate layers of Al x Ga 1-x N, and n-and p-type doping of these alloys is typically required. Experimental results indicate that doping efficiencies in Al x Ga 1-x N are lower than in GaN. We address the cause of these doping difficulties, based on results from first-principles densityfunctional-pseudopotential calculations. For n-type doping we will discuss doping with oxygen, the most common unintentional donor, and with silicon. For oxygen, a DX transition occurs which converts the shallow donor into a negatively charged deep level. We present experimental evidence that oxygen is a DX center in Al x Ga 1-x N for x>~0.3. For p-type doping, we find that compensation by nitrogen vacancies becomes increasingly important as the Al content is increased. We also find that the ionization energy of the Mg acceptor increases with alloy composition x. To address the limitations on p-type doping we have performed a comprehensive investigation of alternative acceptor impurities; none of the candidates exhibits characteristics that surpass those of Mg in all respects.

show abstract

Section: Alternative Acceptorsmentioning

confidence: 99%

Doping of AlGaN Alloys

Walle

Stampfl

Neugebauer

et al. 1999

MRS Internet j. nitride semicond. res.

View full text Add to dashboard Cite

show abstract

“…Optically measured Zn level in GaN is also indicated in this figure. 27 To determine the binding energy of the Zn acceptor-bound exciton in AlN, we have measured the temperature dependence of the I 1 emission intensity in Zn doped AlN. The spectral peak position is red-shifted with increasing temperature following the variation of the bandgap.…”

Section: Zn-doped Alnmentioning

confidence: 99%

Achieving conductive high Al-content AlGaN alloys for deep UV photonics

2007

View full text Add to dashboard Cite

Recent progresses in epitaxial growth and fundamental studies on electrical and optical properties of high Al-content AlGaN alloys with Si, Mg, and Zn doping are presented. For Si doped Al x Ga 1-x N, the Si activation energy was determined for x = 0 up to 1, and the resistivity of n-Al x Ga 1-x N was found to increases by one order of magnitude when Al content is increased by ~ 8%. From photoluminescence (PL) studies, three groups of deep impurity transitions were observed, related with deep level acceptors involving cation vacancy and its complexes: (V III ) 3-, (V III -complex) 2 , and (V III -complex) 1-, which are electron traps and compensating centers. By optimizing the growth processes to reduce the densities of cation vacancy and its complexes, the n-type conductivity of Al x Ga 1-x N was significantly improved. A record low room temperature n-type resistivity of 0.0075 Ω·cm has been obtained for Al 0.7 Ga 0.3 N, and n-type conduction in pure AlN has also been achieved. We also review the electrical and optical measurement results of Mgdoped AlGaN and AlN. It was found that the overall material quality and conductivity of Mg-doped AlN are strongly correlated with the PL emission intensity of the nitrogen vacancy (V N 3+ ) related transition. Improved conductivity was obtained by suppressing the V N 3+ related emission line, which was attributed to the reduced hole compensation by V N 3+ . With the identification of the emission peaks associated with V N 3+ hole compensating centers, the p-type conductivity of high Al-content AlGaN alloys was improved by monitoring and suppressing the intensity of the V N 3+ related emission lines. P-type conduction in Al x Ga 1-x N (x > 0.7) was confirmed at elevated temperatures (> 700 K). The possibility of using Zn as an alternative p-type dopant was also studied. It was found that contrary to the calculation, the energy level of Zn acceptor in AlN was about 0.74 eV, which is 0.23 eV deeper than Mg level in AlN.

show abstract

“…Zn-doped epitaxial GaN films are reported to have a dominant blue-violet emission band centered at $ 2.89 eV [4]. Hiramatsu et al have grown undoped and Zn-doped GaN films on sapphire substrates by metal organic vapor phase epitaxy (MOVPE) and reported that the Zn-doped GaN films exhibit three cathodoluminescence (CL) bands at $365, $425, and 4485 nm, corresponding to the emissions due to near band edge, violet, and blue to green, respectively [5].…”

Section: Introductionmentioning

confidence: 99%