Physical Properties control of II-VI Compound Semiconductors for Blue Light-Emitting-Devices

在II-VI族化合物中，ZnSe和ZnS在蓝色发光二极管中具有最大的应用潜力。对于器件应用，重要的是控制这些材料的导电类型和电阻率。我们研究了金属有机化学气相沉积（MOCVD）法生长受主掺杂的ZnSe和施主掺杂的ZnS薄膜，取得了以下几项重要结果：1。受主掺杂ZnSe：我们已经研究了p型ZnSe薄膜的生长，通过使用氮（N）和锂（Li）作为受主杂质。首先，用NH_3作掺杂剂生长了N掺杂的ZnSe薄膜，低温光致发光测试表明，氮原子在ZnSe中起浅受主的作用，同时也在高N掺杂的薄膜中引入了与氮杂质有关的拜特深中心。在Li掺杂的ZnSe的生长的情况下，使用环己基Li作为掺杂剂。到目前为止，人们一直认为Li是ZnSe中的两性杂质。然而，人们发现，锂原子纳入ZnSe薄膜作为浅受体通过光致发光性能。此外，还发现Li掺杂的ZnSe中与Zn空位相关的深中心强度显著降低. ZnS的施主掺杂：本文研究了用MOCVD法生长施主掺杂ZnS薄膜及其性质。使用三甲基铝和HCl作为供体掺杂剂源。Al掺杂和Cl掺杂的ZnS薄膜都可以生长出电阻率低至1.0cm左右的薄膜.此外，与浅施主能级相关的激子发射和来自自激活中心的发射是低温光致发光光谱中的主要峰。

Of the II-VI compounds, ZnSe and ZnS have the greatest potential for use in blue light-emitting-diodes. For device applications, it is important to control both conductive type and resistivity of these materials. We have investigated growth of acceptor doped ZnSe and donor doped ZnS films by Metalorganic Chemical Vapor Deposition (MOCVD), and obtained several important results as follows;1. Acceptor doping to ZnSe: We have examined the growth of p-type ZnSe films by using nitrogen (N) and lithium (Li) as acceptor impurtites. First, growth of N-doped ZnSe films by using NH_3 as a dopant has been carried out.It has been shown that the njtrogen atoms act as shallow acceptors in ZnSe through low-temperature photoluminescence measurements, byt some deep centers related to the nitrogen impurity are also introduced into highly N-doped films. In case of the growth of Li-doped ZnSe, cyclopentadienly Li was used as a dopant. Up until now, it has been said that Li is an amphoteric impurity in ZnSe. However, it was found that the lithium atoms incorporated into the ZnSe films act as shallow acceptors through the photoluminescence properties. Furthermore, it was also found that the intensities from deep centers related to Zn-vacancy are remarkably reduced in Li-doped ZnSe.2. Donor doping to ZnS: Growth and properties of donor doped ZnS films by MOCVD have been investigated. Trimethylaluminum and HCl were used as donor dopant sources. Both Al- and Cl- doped ZnS films with resistivity as low as about 1 .cm can be grown. Furthermore, an excitonic emission related to a shallow donor level and emission from self-activated centers are dominant peaks in the low-temperature photoluminescence spectrum.