QUANTUM PHOTOYIELD OF DIAMOND(111) - STABLE NEGATIVE-AFFINITY EMITTER
QUANTUM PHOTOYIELD OF DIAMOND(111) - STABLE NEGATIVE-AFFINITY EMITTER
复制标题
DOI：
10.1103/physrevb.20.624
复制
发表时间：
1979-01-01
影响因子：
3.7
通讯作者：
EASTMAN, DE
中科院分区：
文献类型：
--
作者：
HIMPSEL, FJ;KNAPP, JA;EASTMAN, DE
给出了未重构金刚石(111)表面(IIb型宝石级蓝白半导体)的量子光产额和二次电子分布。这种化学惰性表面表现出负的电子亲和力，导致稳定的量子产额在9 eV时从光阈值(5.5 eV)线性增加到∼20%，对于13≲hν≲35 eV有很大的产额40%-70%。对于所有的光子能量，二次电子能量分布在导带最小处(∼1分钟=5.50±0.05 eV，比价带最大值Δ25‘高5.50±0.05 eV)显示出占主导地位的Γ0.5eV宽的发射峰。与最近的自洽计算不同[J.Ihm，SG Louie和ML Cohen，Phys.在基态禁带(费米能级高于Γ25‘以上1 eV)中没有观察到具有电离能的占据本征表面态。同样，测量的光阈值(E vac−Γ25‘)明显小于计算的(7.0±0.7 eV)。
Quantum photoyield and secondary-electron distributions are presented for an unreconstructed diamond (111) surface (type-II b, gem-quality blue-white semiconductor). This chemically inert surface exhibits a negative electron affinity, resulting in a stable quantum yield that increases linearly from photothreshold (5.5 eV) to∼ 20% at 9 eV, with a very large yield of∼ 40%-70% for 13≲ h ν≲ 35 eV. For all photon energies, secondary-electron energy distributions show a dominant∼ 0.5-eV-wide emission peak at the conduction-band minimum (Δ 1 min= 5.50±0.05 eV above the valence-band maximum Γ 25′). In contrast with recent self-consistent calculations [J. Ihm, SG Louie, and ML Cohen, Phys. Rev. B 17, 769 (1978)] no occupied intrinsic surface states with ionization energies in the fundamental gap (the Fermi level was 1 eV above Γ 25′) were observed. Likewise, the measured photothreshold (E vac− Γ 25′) is significantly smaller than calculated (7.0±0.7 eV).