高掺杂Ga对ZnSe:Ga,Cu晶体中深中心发射的影响

本文研究了高掺杂Ga对ZnSe:Ga,Cu晶体中深中心光致发光谱带的影响。首次在高掺杂ZnSe:Ga,Cu中观察到了Cu-G带峰值位置随Ga浓度增大向长波方向移动的现象,并把它归因于高浓度的Ga和Cu相互作用,产生了谱峰为5580Å的新发射带,其半高宽(FWHM)大于Cu-G谱带的半高宽。此外还得到,随着Cu浓度增加,Cu-G带与Cu-R带强度之比减小。文中指出,Ga浓度较低时,ZnSe:Ga,Cu晶体与ZnSe:Cu晶体有相同的Cu深中心发射规律,即随着Cu浓度增大,Cu-G带与Cu-R带的强度比增大,由Cu-R发射带占优势逐渐过渡到Cu-G发射带占优势。

THE EFFECT OF HIGH Ga CONCENTRATION ON DEEP CENTER EMISSION IN ZnSe:Ga,Cu CRYSTALS

In recent years,interest in ZnSe has increased considerably as a potential candidate for blue light emitting diodes. Cu and Ga are important impurities in crystals of ZnSe.In this paper we study the effect of high Ga concentration on deep center emission in ZnSe:Ga,Cu crystals.Nominally undoped ZnSe boule crystals were grown by sublimation.ZnSe dice with dimension of 3×3×1mm3 were cut from the boules,and heated in molten alloy of zinc, gallium and copper with different concentration of Ga and Cu(Ga/Zn and Cu/Zn in weight respectively)to introduce the impurities and to obtain their low resistivities. Photoluminescence (PL)spectra in ZnSe crystals were measured using a Model 44W spectrometer with a C31034 pho-tomultiplier. A N2 pulsed laser of Model QJD-9 was used as the excitation source.Fig.1 shows the PL spectra of ZnSe:Ga,Cu with different Cu concentration when Ga concentration is equal to Cu.It is found that the Cu-G band is prominent in ZnSe crystal with high Cu concentration, while the Cu-R band is prominent in ZnSe crystals with low Cu concentration. This means that the intensity ratio of Cu-G band to Cu-R band increases with increasing Cu concentration,which was reported by Wang et al[12]. and Yamaguchi et al[1,2]. in ZnSe:Cu crystals.