Vacancy-type defects introduced by plastic deformation of GaN studied using monoenergetic positron beams

Abstract

Vacancy-type defects in plastically deformed GaN were studied using monoenergetic positron beams. Dislocations with a Burgers vector of (1/3)[1 210] were introduced by applying compressive stress at 950 C. Measurements of Doppler broadening spectra of the annihilation radiation and positron lifetime spectra showed that both microvoids and Ga-vacancy-type defects were introduced into the deformed sample. The former defects are considered to be introduced through an agglomeration of vacancies introduced by dislocation motions. We observed a distribution of the mean positron lifetime along a long side of the deformed sample, which corresponds to the stress distribution during the deformation. In photoluminescence studies, yellow-band luminescence (2.2 eV) decreased due to the deformation. The suppression of this band was attributed to the vacancy-type defects and/or dislocations introduced by the deformation. V C 2013 AIP Publishing LLC. [http://dx.

Carrier Trapping by Vacancy‐Type Defects in Mg‐Implanted GaN Studied Using Monoenergetic Positron Beams

“…The longest lifetime was obtained at 500–550 ps. A similarly long positron lifetime was observed for plastically deformed GaN, attributing to positron trapping by large vacancy clusters or microvoids. For the present samples, the open spaces adjacent to secondary defects are also candidates as positron trapping centers.…”

Simple way of finding Ba to Si deposition rate ratios for high photoresponsivity in BaSi2 films by Raman spectroscopy

“…Details of the growth procedure of BaSi 2 films were reported previously. [17][18][19][20][21][22][23] During the MBE growth, R Si was fixed to be 0.9 nm min −1 and R Ba was varied from 0.9 to 3.2 nm min −1 , giving a variation of R Ba /R Si from 1.1 to 3.6. In this study, we also conducted MBE at 650 °C, which is 70 °C higher than the temperature used in our previous experiments.…”

“…Through this method, vacancy-type defects of various semiconductors (i.e., GaN, AlON x , CIGS) have been investigated. [22][23][24][25][26] Figure 1(a) shows the S parameters of BaSi 2 films grown at T S = 580 °C with various R Ba /R Si . We found that the optical properties changed markedly as R Ba /R Si values were varied, and the maximum photoresponsivity was achieved at R Ba /R Si = 2.2 for samples grown at T S = 580 °C, as shown in Fig.…”

Development of combinatorial defect analysis with an intense positron microprobe

“…(i) defect/pore analysis of small samples [10][11][12][13][14][15][16] (ii) defect/pore analysis for many local spots in large samples [3,[17][18][19] (iii) in-situ (in-air) defect/pore analysis of thin films [20,21] In the present study a new analytical method which we call the combinatorial technique is described. This combinatorial defect/pore analytical method can be categorized as follows;…”