Effects of nonuniform distribution of quantum well and quantum wire base on infrared photodetectors under dark conditions

摘要

This paper presents the effects of uniformity and nonuniformity distribution of quantum well (QW) and wire (QR) base on quantum infrared photodetectors under dark conditions. These detectors are quantum well infrared photodetectors (QWIP) and quantum wire infrared photodetectors (QRIP). Analytical expressions for dark current characteristics of the considered devices are implemented. Additionally, the proposed results are validated against published results in literature and high agreement is accomplished. The potential distribution in QWIP active region depends on weak non-locality approach. Also, the effect of electrons concentration above the barriers on the performance of QRIP is considered. The nonuniformity parameter of QRIP is computed. Moreover, the uniformity and nonuniformity distributions effects of QRs and QWs on dark current ratio between QRIP and QWIP are estimated. This current ratio is changed by uniformity and nonuniformity distribution of QWs and QRs. It is noted that dark current ratio between QRIP and QWIP decreases with applied bias voltage. Hence, the QWIP device is affected by applied bias voltage greater than QRIP. However, this current ratio increases with temperature. Accordingly, the QRIP device is influenced by temperature larger than QWIP. It is noticed that dark current ratio under uniformity distribution is smaller than this ratio under nonuniformity distribution for both QRs and QWs. So, the nonuniformity problem within QRs is a great challenge that must be addressed. Also, the nonuniformity distribution introduces limits to QRIP device characteristics. The results demonstrate that zero value of dark current ratio is attained with zero value of nonuniformity parameter. Also, the dark current of QRIPs is found to be greater than of QWIP structures under large variation of nonuniformity distribution. Even though, this parameter is approximated to 1 under uniform distribution of QWs and QRs. It is observed that nonuniformity distribution parameter is vanished up to 80 K. So, the dependence of the operating temperature on the number of electrons occupied by each QR is evaluated. The obtained results confirm that the applied bias voltage decreases this challenge to some extent. Besides, parameters optimization for QWIPs and QRIP is of primary concern. Therefore, the devices performance is improved. Consequently, the operations of underlined infrared photodetectors are robust against noise sources in far infrared spectrum.