Sandall Ian, Ng Jo Shien, David John P R, Tan Chee Hing, Wang Ting, Liu Huiyun
Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK.
Opt Express. 2012 May 7;20(10):10446-52. doi: 10.1364/OE.20.010446.
The optical and electrical properties of InAs quantum dots epitaxially grown on a silicon substrate have been investigated to evaluate their potential as both photodiodes and avalanche photodiodes (APDs) operating at a wavelength of 1300 nm. A peak responsivity of 5 mA/W was observed at 1280 nm, with an absorption tail extending beyond 1300 nm, while the dark currents were two orders of magnitude lower than those reported for Ge on Si photodiodes. The diodes exhibited avalanche breakdown at 22 V reverse bias which is probably dominated by impact ionisation occurring in the GaAs and AlGaAs barrier layers. A red shift in the absorption peak of 61.2 meV was measured when the reverse bias was increased from 0 to 22 V, which we attributed to the quantum confined stark effect. This shift also leads to an increase in the responsivity at a fixed wavelength as the bias is increased, yielding a maximum increase in responsivity by a factor of 140 at the wavelength of 1365 nm, illustrating the potential for such a structure to be used as an optical modulator.
对在硅衬底上外延生长的铟砷量子点的光学和电学性质进行了研究，以评估其作为工作在1300纳米波长的光电二极管和雪崩光电二极管（APD）的潜力。在1280纳米处观察到5毫安/瓦的峰值响应率，吸收尾延伸至1300纳米以上，而暗电流比硅基锗光电二极管报道的低两个数量级。这些二极管在22伏反向偏压下表现出雪崩击穿，这可能由砷化镓和铝镓砷势垒层中发生的碰撞电离主导。当反向偏压从0增加到22伏时，测量到吸收峰有61.2毫电子伏特的红移，我们将其归因于量子限制斯塔克效应。随着偏压增加，这种红移还会导致固定波长下响应率增加，在1365纳米波长处响应率最大增加140倍，说明了这种结构用作光调制器的潜力。
