Data for functional TiO2 embedded Silicon photodetectors under varying illumination and bias conditions

In this data in brief (DIB) article, major photodetector (PD) characteristics of anisotype (Ag/n-TiO2/p-Si/Al), isotype (Ag/n-TiO2/n-Si/Ag) and M-S-M type (Ag/p-Si/Al) structures under reverse bias conditions (−1 to −5 V) over a broad spectral region (300–800 nm) have been presented. Critical figures of merit like current-voltage (IV), responsivity (R), detectivity (D), gain, sensitivity (S), linear dynamic range (LDR), normalized photo to dark current ratio (NPDR) and noise equivalent power (NEP) of TiO2 embedded Si PDs are presented in graphical forms. I–V characteristics of PDs under dark and monochromatic illuminations (365, 425, 515 and 600 nm) were acquired by using source measure unit (Kithley). Internal gain was deduced from photoresponse spectra which were recorded with the help of Potentiostat/Galvanostat (PGSTAT302N, Autolab) under monochromatic illumination at 100 Hz chopping frequency. Quantum efficiency instrument supplied by Optosolar was utilized to accurately measure the spectral responsivity and detectivity of PDs in wide spectral region (300–1100 nm). Please refer our main article [1] to understand the role of functional nanocrystalline TiO2 films on the performance of the photodetectors.


a b s t r a c t
In this data in brief (DIB) article, major photodetector (PD) characteristics of anisotype (Ag/n-TiO 2 /p-Si/Al), isotype (Ag/n-TiO 2 /n-Si/Ag) and M-S-M type (Ag/p-Si/Al) structures under reverse bias conditions (À1 to À5 V) over a broad spectral region (300 e800 nm) have been presented. Critical figures of merit like current-voltage (IV), responsivity (R), detectivity (D), gain, sensitivity (S), linear dynamic range (LDR), normalized photo to dark current ratio (NPDR) and noise equivalent power (NEP) of TiO 2 embedded Si PDs are presented in graphical forms. IeV characteristics of PDs under dark and monochromatic illuminations (365, 425, 515 and 600 nm) were acquired by using source measure unit (Kithley). Internal gain was deduced from photoresponse spectra which were recorded with the help of Potentiostat/Galvanostat (PGSTAT302N, Autolab) under monochromatic illumination at 100 Hz chopping frequency. Quantum efficiency instrument supplied by Optosolar was utilized to accurately measure the spectral responsivity and detectivity of PDs in wide spectral region (300 e1100 nm). Please refer our main article [1] to understand the role of functional nanocrystalline TiO 2 films on the performance of the photodetectors.

Data
Functioning of low electron affinity nanocrystalline TiO 2 embedded Si PDs were studied in our recent article [1] in which Ag/n-TiO 2 /p-Si/Al anisotype junction was found to be most efficient amongst all PDs. This DIB article includes all the analyzed PD parameters which were utilized to get insight into a role of functional TiO 2 film on the overall performance of each Si PDs. Briefly, to trace the exact contribution of a thin TiO 2 layer, performance of Ag/n-TiO 2 /p-Si/Al was compared with Ag/p-Si/Al and hence responsivity (R) and detectivity (D) of such devices (D1 and D3) are presented in Figs. 1 and 2, respectively. Fig. 1 shows the variation in responsivity (in A/W) of the PDs with varying bias under the illumination of typically selected wavelengths. Viz., 360, 400, 500, 600 and 700 nm representing UV, blue, green, red and near infrared (NIR) regions, respectively. Detectivity (in Jones) variation of such devices is shown in Fig. 2 in the form of bar charts for the mentioned lights and reverse bias conditions. Photocurrent gain for all three configurations of Si PDs are presented in Fig. 3 consecutively from left to right for the devices Ag/n-TiO 2 /p-Si/Al (D1), Ag/n-TiO 2 /n-Si/Ag (D2) and Ag/p-Si/Al (D3), respectively. Enhancement in the photocurrent against the dark current of each PD while operated in the reverse bias can be readily looked into from these graphs. Sensitivity of any PD believed to be one of the most crucial figures of merit and thus Fig. 4 includes the sensitivity data of each PD under the monochromatic illumination from broad spectral range. Fig. 5 shows very important behavior of PDs in the form of linear dynamic range which signifies the degree of linearity in PD operation against its noise. It includes LDR response of all the devices operated under reverse bias and predefined illuminating wavelengths.

Value of the Data
The data presented in this data article is of high importance to the researchers as well as industries working towards the development of highly sensitive, responsive, ultrafast, broadband Si photodetectors.
Detailed figures of merit of three configurations of Si PDs under varying illumination and reverse bias conditions are quantitatively analyzed and graphically exemplified over broadband region. Spectral responsivity and detectivity are the key PD parameters to be used as ready reckoner to see the effect of functional TiO 2 film on overall performance of Si PDs. Availability of the PDs data over a broadband range accelerates their direct integration in modern electronics and application based design of PDs can be directly chosen for the future developments.         Quantitatively analyzed normalized photo to dark current ratio (NPDR) and noise equivalent power (NEP) are shown in Figs. 6 and 7, respectively. Variation in NPDR and NEP with applied bias is highly important to trace out the ability of designed PD in handling the noise level and thus enabling a quicker response to the actual signal. At the end, IV characteristics of each of the PDs under varying illumination and dark conditions are shown in Fig. 8.
All the acquired raw data and analyzed figures of merit like responsivity, detectivity, gain, sensitivity, LDR, NPDR and NEP of designed PDs are given in Tables-1 to 7, respectively.

Experimental design, materials, and methods
Monocrystalline Si wafers of p and n-type were used as substrates to fabricate PDs of the configurations discussed in the main manuscript [1]. Ohmic metal contacts on such Si wafers were obtained by sputtering thin layers of aluminum (Al) and silver (Ag), appropriately. High purity Ti (99.995% pure,  Sigma Aldrich) was sputtered at constant power of 150 W and 5 mT working pressure with predefined Ar flow for 15 min. To convert Ti thin films into titanium dioxide (TiO 2 ), Ti coated Silicon films were post treated in vacuum furnace at 700 C for 10 min.