Piezoreflectance study of InP near the absorption edge

Chung, Sang-Jo; Lin, Der-Yuh; Huang, Y. S.; Tiong, K. K.

doi:10.1088/0268-1242/11/12/015

Cited by 13 publications

(12 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5(a)-5(c) and the obtained values of À j ð0Þ and À j LO as well as the numbers for j AC and Â j LO are listed in Table III. For comparison, the values of À LO (in terms of HWHM) for ZnSe, 9,26,27) Zn 0:56 Cd 0:44 Se, 9) CdSe (A exciton), 22) GaAs, 28) In 0:06 Ga 0:94 As, 8) InP, 29) and GaN 30,31) from other works are also included in Table III. The values of À j ð0Þ for the beryllium containing samples are much larger than those of beryllium free sample due mainly to the poorer crystalline quality of the Be-incorporated samples.…”

Section: Resultsmentioning

confidence: 99%

Temperature Dependence of the Band-Edge Transitions of ZnCdBeSe

Hsieh

Huang

et al. 2004

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

We have characterized the temperature dependence of band-edge transitions of three (Zn 0:38 Cd 0:62 ) 1Àx Be x Se II-VI films with different Be concentrations x by using contactless electroreflectance (CER) and piezoreflectance (PzR) in the temperature range of 15 to 450 K. By a careful comparison of the relative intensity of PzR and CER spectra, the identification of light-hole (lh) and heavy-hole (hh) character of the excitonic transitions of the samples has been accomplished. The temperature dependence analysis yields information on the parameters that describe the temperature variations of the energy (including thermal expansion effects) and broadening parameter of the band edge transitions of ZnCdBeSe. The study shows that Be incorporation can effectively reduce the rate of temperature variation of the energy gap.

show abstract

Section: Resultsmentioning

confidence: 99%

Temperature Dependence of the Band-Edge Transitions of ZnCdBeSe

Hsieh

Huang

et al. 2004

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

show abstract

“…above the steep slope) suggests that it should not vary with the concentration at a moderate doping level, when the Fermi level is still below the conduction band edge. The experimentally observed temperature variations of E g (T ) and ∆(n, T ), are proportional to the population of thermally excited phonons and can be estimated 11,12 using Einstein's model for the phonon spectrum. Variations of E g with the dop-ing concentration reflect the effect of band-gap narrowing combined with Fermi energy shift due to filling of the impurity band, 13 while the increase of ∆ is attributed to the combined effect of the adiabatic random phonon potential and the random potential produced by concentration fluctuations.…”

mentioning

confidence: 99%

Urbach tail studies by luminescence filtering in moderately doped bulk InP

Subashiev

Semyonov

Chen

et al. 2010

Applied Physics Letters

View full text Add to dashboard Cite

The shape of the photoluminescence line registered from a side edge of InP wafer is studied as function of the distance from the excitation spot. The observed red shift in the luminescence maximum is well described by radiation filtering and is consistent with the absorption spectra. Our method provides an independent and accurate determination of the Urbach tails in moderately doped semiconductors.Studies of the optical absorption spectra near the interband absorption edge are widely used for characterization of semiconductor materials. [1][2][3] The spectral dependence at low-energy absorption edge is well approximated by the Urbach exponential decay. 4 However, the interband absorption usually overlaps with residual absorption by free carriers, masking the true dependence of the absorption tail. In doped samples, the absorption tail is additionally broadened and this effect is also masked by the residual electronic absorption.Available theories 5-8 do not provide description of the interband absorption tailing in the entire energy range from interband to deep tails. Still, they give an insight on the nature of the bandgap fluctuations causing the tailing. Tailing with Gaussian-like asymptotics is characteristic of classical potential fluctuations, 5 whereas exponential decrease with square-root energy dependence in the exponent is indicative of quantum effects in the band tailing. 6,7 Temperature variations of the tailing are accounted for by the adiabatic potential of thermally excited phonons. 8 In a limited experimental range near the fundamental edge the observed absorption spectra may not differ noticeably from the Urbach law, 7 but the temperature and the concentration dependence of the tailing parameters can be very informative. Therefore, accurate studies of the tailing dependence are highly desirable.In this letter we describe an alternative experimental method for studying the semiconductor absorption edge by measuring the red shift of the peak of the luminescence line, registered from the side edge of the wafer. This shift is sensitive to the sample transparency at the peak wavelength, which is in the region where residual absorption dominates. We show that for moderately doped n-InP wafers this technique provides an accurate determination of the Urbach tailing energy.We used 350 µm-thick InP wafers, doped n-type (S) in the range n = 2 × 10 17 to 6 × 10 18 cm −3 and measured the reflection and the transmission spectra to evaluate the absorption coefficient α. 9 For all moderately doped samples, n ≤ 2 × 10 18 cm −3 , in the temperature range 78 to 320 K, the absorption edge exhibits an Urbach-type energy dependence in the range α = 10 to 100 cm −1 . For lower doped samples, n < 10 18 cm −3 , the observed a) Electronic

show abstract

“…For T = 78 K the constant c = 71.4 [12], giving an estimate of ∆E g ≈ 20 meV for the depleted fluctuation region. We see that the effect is sufficient to account for the blue shift of luminescence lines at T = 78 K. For T = 300 K one has c = 22.5 and the bandgap narrowing effect is reduced [33].…”

Section: Deviation From Thermal Equilibriummentioning

confidence: 78%

“…One can see that in the temperature interval 300 ≥ T ≥ 150 K the values of ∆(n, T ) are increased by ≈ 1.5 meV as compared to the undoped sample, while the difference in E g (T, n) is minimal. Variations of both E g (n, T ) and ∆(n, T ) with the temperature and the doping can be described [32,33] in the Einstein model for lattice vibrations,…”

Section: Discussion: Effects Of Spectral Filteringmentioning

confidence: 99%

Edge excitation geometry for studying intrinsic emission spectra of bulk n-InP

Semyonov

Subashiev

Chen

et al. 2014

Journal of Luminescence

View full text Add to dashboard Cite

The shape of the photoluminescence line excited at an edge face of InP wafer and registered from the broadside is used to investigate the intrinsic emission spectrum. The procedure is much less sensitive to the surface properties and the carrier kinetics than the conventional methods used with the reflection or transmission geometry of photoluminescence. Our method provides a tool for studying the effects of non-equilibrium distribution of minority carriers in doped direct-band semiconductors.

show abstract

Piezoreflectance study of InP near the absorption edge

Cited by 13 publications

References 32 publications

Temperature Dependence of the Band-Edge Transitions of ZnCdBeSe

Temperature Dependence of the Band-Edge Transitions of ZnCdBeSe

Urbach tail studies by luminescence filtering in moderately doped bulk InP

Edge excitation geometry for studying intrinsic emission spectra of bulk n-InP

Contact Info

Product

Resources

About