摘要
本文利用变温Hall测量,证实了我们用MOCVD法生长的No.87—39A ZnSe-ZnS应变超品格(SLS)具有P型导电特性。文中试图从应变超晶格的临界厚度,电学参数、能带结构等方面解释ZnSe-ZnS SLS反型的原因。文中指出,这时的受主能级可能处于ZnS层靠近界面附近,这些受主能级的位置比ZnSc阱中满带顶能量低。
ZnSe-ZnS strained-layer superlattice was thought to be an important optoelectronic material of blue region,It is very difficult for us to obtain p-type ZnSe semiconductor.Some scientists have manufactured the p-type ZnSe materials.(see Table 1) so far.Using the Van De Pauw -Hall measurement with different temperature.we verified that the ZnSe -ZnS SLS(No.87039, undoping) grown by atmospheric pressure MOCVD was a p-type semiconductor material. The electrical parameters are shown in Table 2. The concentration of the hole carriers is above 1018 cm-3 The drift-mobility of the hole carriers is 30cm2/V. s. The acceptor-dissociated energy is 8 meV. The well width and barrier width are above 60AWe think that the hang-bonds will arise in the interfaces of ZnSe-ZnS hetrojunctions when the thicknesses of the wells or barries of ZnSe--ZnS SLS are above the critical thickness. The hang-bonds may act as acceptors when they capture the electrons of the valence. The crystal lattice constant of ZnSe is greater than that of ZnS, so the hang-bonds appear in ZnS layers. The acceptor levels are in the nearby region of ZnSe-ZnS hetrojunction's interfaces, and lower than the valence maximum of ZnSe. The electrons spontaneously fall in the acceptor levels from the valence of ZnSe(see Fig.1(a)). The acceptors are dissociated indendent of thermal energies, which interpretted that the hole's carrier concentration weakly vanes with temperature. The hang-bonds result in the extracharges,which scatter the hole carriers,and make the mobility too small.
出处
《发光学报》
EI
CAS
CSCD
北大核心
1990年第4期295-299,共5页
Chinese Journal of Luminescence
